<p><em>"The core of the engineering mind-set is what I call modular systems thinking. It’s not a singular talent, but a melange of techniques and principles. Systems-level thinking is more than just being systematic; rather, it’s about the understanding that in the ebb and flow of life, nothing is stationary and everything is linked. The relationships among the modules of a system give rise to a whole that cannot be understood by analyzing its constituent parts."</em></p>

<p><strong>It means to be able to break down a big system into its sections and putting it back together</strong>. The target is to identify the strong and weak links: how the sections work, don’t work, or could potentially work and applying this knowledge to engineer useful outcomes.</p>
<p>There is no engineering method, so modular systems thinking varies with contexts.</p>

Thinking in Systems

<ul>
<li>The ability to see a structure where there’s nothing apparent.</li>
<li>Adeptness at designing under constraints.</li>
<li>The capacity to hold alternative ideas in your head and make considered judgments.</li>
</ul>

Fundamental Properties of the Engineering Mind-Set

<!DOCTYPE html><html>
<body>
  <div>
    <header>
      <div>
        <div>
          <a href="/"><svg>
<style>.st0{fill:#CC3232;}</style>
<path></path>
</svg>

</a>
        </div>
        <ul>
                                    <li><a href="/blog/">Articles</a></li>
                          <li><a href="/books/">Books</a></li>
                          <li><a href="/knowledge-project/">Podcast</a></li>
                                              <li><a href="/membership"> Community</a></li>
            
                              <li>
                    <a href="https://fs.blog/?memberful_endpoint=auth">Member Login</a>
                  </li>
                                <li><a href="/search"><i></i></a></li>  
              </ul>

              <div>
                <a href="#"><div></div></a>
                <nav>
                  <div>
                    <ul>
                                                                        <li><a href="/blog/">Articles</a></li>
                                                  <li><a href="/books/">Books</a></li>
                                                  <li><a href="/knowledge-project/">Podcast</a></li>
                                                                                                                      <li><a href="https://fs.blog/members/">Member Login</a></li>
                                                                    <li><a href="/search">Search</a></li>  
                    </ul>  
                  </div>
                </nav>
              </div>
            </div>
          </header> 
          <div><div>
	<main>
		<div>
			<div>
									<ul>
													<li><a href="/mental-models/">Mental Models</a></li>	
													<li><a href="/smart-decisions/">Decision Making</a></li>	
													<li><a href="/reading/">Reading Better</a></li>	
													<li><a href="/best-articles/">Best Articles</a></li>	
													<li><a href="/random-articles">Random Article</a></li>	
													<li><a href="/tags/">Tags</a></li>	
											</ul>
							</div>
		</div> 
		<div>
			<div>
			</div>
		</div> 
		<div>
			<div>
				<div>
											<div>
							<div><span><a href="https://fs.blog/blog/">Blog</a></span><span>  </span><span><a href="https://fs.blog/category/thinking/">Thinking</a></span><span>  </span><span><span>The Three Essential Properties of the Engineering Mind-Set</span></span></div>						</div>
										<div>
													<article>

<div>

<h1>The Three Essential Properties of the Engineering Mind-Set</h1>
<div>

<span>Reading Time:  4 minutes</span>
</div>
</div>

<div>
<p><em>Engineers use a unique mode of thinking based on seeing everything as a system. They see structures that aren’t apparent to the layperson, they know how to design under constraints, and they understand trade-offs. </em><em>Adopting an engineering mindset can help you in any field.</em></p>
<p>***</p>
<p>In his book <a href="http://www.amazon.com/gp/product/039323987X/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&amp;camp=1789&amp;creative=9325&amp;creativeASIN=039323987X&amp;linkCode=as2&amp;tag=farnamstreet-20&amp;linkId=DVAFNEHYYJFDRJTI">Applied Minds: How Engineers Think</a>, Guru Madhavan explores the mental tools of engineers that allow engineering feats. His framework is built around a flexible intellectual tool kit called modular systems thinking.</p>
<blockquote><p>The core of the engineering mind-set is what I call modular systems thinking. It’s not a singular talent, but a melange of techniques and principles. Systems-level thinking is more than just being systematic; rather, it’s about the understanding that in the ebb and flow of life, nothing is stationary and everything is linked. The relationships among the modules of a system give rise to a whole that cannot be understood by analyzing its constituent parts.</p></blockquote>
<h2>Thinking in Systems</h2>
<p>Thinking in systems means that you can deconstruct (breaking down a larger system into its modules) and reconstruct (putting it back together).</p>
<blockquote><p>The focus is on identifying the strong and weak links—how the modules work, don’t work, or could potentially work—and applying this knowledge to engineer useful outcomes.</p></blockquote>
<p>There is no engineering method, so modular systems thinking varies with contexts.</p>
<blockquote><p>Engineering Dubai’s Burj Khalifa is different from coding the Microsoft Office Suite. Whether used to conduct wind tunnel tests on World Cup soccer balls or to create a missile capable of hitting another missile midflight, engineering works in various ways. Even within a specific industry, techniques can differ. Engineering an artifact like a turbofan engine is different from assembling a megasystem like an aircraft, and by extension, a system of systems, such as the air traffic network.</p></blockquote>
<h2>The Three Essential Properties of the Engineering Mind-Set</h2>
<p><strong>1. The ability to see a structure where there’s nothing apparent.</strong></p>
<blockquote><p>From haikus to high-rise buildings, our world relies on structures. Just as a talented composer “hears” a sound before it’s put down on a score, a good engineer is able to visualize—and produce—structures through a combination of rules, models, and instincts. The engineering mind gravitates to the piece of the iceberg underneath the water rather than its surface. It’s not only about what one sees; it’s also about the unseen.</p>
<p>A structured systems-level thinking process would consider how the elements of the system are linked in logic, in time, in sequence, and in function—and under what conditions they work and don’t work. A historian might apply this sort of structural logic decades after something has occurred, but an engineer needs to do this preemptively, whether with the finest details or top-level abstractions. This is one of the main reasons why engineers build models: so that they can have structured conversations based in reality. Critically, envisioning a structure involves having the wisdom to know when a structure is valuable, and when it isn’t.</p>
<p>[…]</p>
<p>Consider, for example, the following catechism by George Heilmeier—a former director of the U.S. Defense Advanced Research Projects Agency (DARPA), who also engineered the liquid crystal displays (LCDs) that are part of modern-day visual technologies. His approach to innovation is to employ a checklist-like template suitable for a project with well-defined goals and customers.</p>
<ul>
<li>What are you trying to do? Articulate your objectives using absolutely no jargon.</li>
<li>How is it done today, and what are the limits of current practice?</li>
<li>What’s new in your approach and why do you think it will be successful?</li>
<li>Who cares? If you’re successful, what difference will it make?</li>
<li>What are the risks and the payoffs?</li>
<li>How much will it cost? How long will it take?</li>
<li>What are the midterm and final “exams” to check for success?</li>
</ul>
</blockquote>
<p>This type of structure “helps ask the right questions in a logical way.”</p>
<h2>2. Adeptness at designing under constraints</h2>
<p>The real world is full of constraints that make or break potential.</p>
<blockquote><p>Given the innately practical nature of engineering, the pressures on it are far greater compared to other professions. Constraints—whether natural or human-made—don’t permit engineers to wait until all phenomena are fully understood and explained. Engineers are expected to produce the best possible results under the given conditions. Even if there are no constraints, good engineers know how to apply constraints to help achieve their goals. Time constraints on engineers fuel creativity and resourcefulness. Financial constraints and the blatant physical constraints hinging on the laws of nature are also common, coupled with an unpredictable constraint—namely, human behavior.</p>
<p>“Imagine if each new version of the Macintosh Operating System, or of Windows, was in fact a completely new operating system that began from scratch. It would bring personal computing to a halt,” Olivier de Week and his fellow researchers at the Massachusetts Institute of Technology point out. Engineers often augment their software products, incrementally addressing customer preferences and business necessities— which are nothing but constraints. “Changes that look easy at first frequently necessitate other changes, which in turn cause more change. . . . You have to find a way to keep the old thing going while creating something new.” The pressures are endless.</p></blockquote>
<h2>3. Understanding Trade-offs</h2>
<p>The ability to hold alternative ideas in your head and make considered judgments.</p>
<blockquote><p>Engineers make design priorities and allocate resources by ferreting out the weak goals among stronger ones. For an airplane design, a typical trade-off could be to balance the demands of cost, weight, wingspan, and lavatory dimensions within the constraints of the given performance specifications. This type of selection pressure even trickles down to the question of whether passengers like the airplane they’re flying in. If constraints are like tightrope walking, then trade-offs are inescapable tugs-of-war among what’s available, what’s possible, what’s desirable, and what the limits are.</p></blockquote>
<p><a href="http://www.amazon.com/gp/product/039323987X/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&amp;camp=1789&amp;creative=9325&amp;creativeASIN=039323987X&amp;linkCode=as2&amp;tag=farnamstreet-20&amp;linkId=DVAFNEHYYJFDRJTI">Applied Minds: How Engineers Think</a> will help you borrow strategies from engineering and apply them to your most pressing problems.</p>

<div>
<svg>
<style>.st0{fill:#CC3232;}</style>
<path></path>
</svg>

</div>

<div>
<div>
<span>Tagged: <a href="https://fs.blog/tag/culture/">Culture</a>, <a href="https://fs.blog/tag/engineering/">Engineering</a>, <a href="https://fs.blog/tag/guru-madhavan/">Guru Madhavan</a>, <a href="https://fs.blog/tag/thinking/">Thinking</a> </span>
</div>
</div>



	


<div>
<a></a>
</div>



</div>
</article>


							
	<nav>
		<h2>Post navigation</h2>
		<div><div><a href="https://fs.blog/2015/06/what-makes-us-happy/">Why it’s easier to describe “what makes us happy” than answer the question “what is happiness?”</a></div><div><a href="https://fs.blog/2015/06/the-double-edge-of-expertise/">Garrett Hardin: The Other Side of Expertise</a></div></div>
	</nav>											</div>
					<div>
						<div>
							<section><h3><span>Sponsored By</span></h3><a href="https://www.roycefunds.com/"><img src="https://149366099.v2.pressablecdn.com/wp-content/uploads/2019/12/160x160Royce-Investment-Partners.png"/></a></section>						</div>
					</div>
				</div> 
			</div>
		</div> 
	</main></div>
</div> 
<div>
	<div>
		<div>
			<h2>Suggested Reading</h2>
			<div>
				


<a href="https://fs.blog/2020/05/pandemic/">
<div>
<h2>Mental Models For a Pandemic</h2>
<span>Reading Time <span>|</span> 8 minutes</span>
<p>Mental models help us understand the world better, something which is especially valuable during times of confusion, like a pandemic. Here’s how to apply mental models to gain a more accurate picture of reality and keep a cool head. *** It feels overwhelming when the world changes rapidly, abruptly, and extensively. The changes come so […]</p>
<p>Continue Reading <i></i></p>
</div> 
</a>



<a href="https://fs.blog/2020/03/find-what-you-truly-value/">
<div>
<h2>What You Truly Value</h2>
<span>Reading Time <span>|</span> 3 minutes</span>
<p>Our devotion to our values gets tested in the face of a true crisis. But it’s also an opportunity to reconnect, recommit, and sometimes, bake some bread. *** The recent outbreak of the coronavirus is impacting people all over the world — not just in terms of physical health, but financially, emotionally, and even socially. […]</p>
<p>Continue Reading <i></i></p>
</div> 
</a>



<a href="https://fs.blog/2020/03/chestertons-fence/">
<div>
<h2>Chesterton’s Fence: A Lesson in Second Order Thinking</h2>
<span>Reading Time <span>|</span> 8 minutes</span>
<p>A core component of making great decisions is understanding the rationale behind previous decisions. If we don’t understand how we got “here,” we run the risk of making things much worse. *** When we seek to intervene in any system created by someone, it’s not enough to view their decisions and choices simply as the […]</p>
<p>Continue Reading <i></i></p>
</div> 
</a>

			</div>
		</div> 
	</div> 
</div>
</div> 



<footer>
	<div>
		<div>
			<div>
				<div>
					<svg>
<style>.st0{fill:#CC3232;}</style>
<path></path>
</svg>

				</div>
				
				<div>
					<h4>Farnam Street</h4>
											<ul>
																								<li><a href="/newsletter/">Newsletter</a></li>
																																<li><a href="/knowledge-project/">Podcast</a></li>
																																<li><a href="/membership">Learning Community</a></li>
																																<li><a href="https://fs.blog/books/">Books</a></li>
																																<li><a href="/speaking">Speaking</a></li>
																																<li><a href="/about">About</a></li>
																					</ul>
									</div>
				
				<div>
					<h4>Categories</h4>
											<ul>
																								<li><a href="/mental-models/">Mental Models</a></li>
																																<li><a href="https://fs.blog/learning">Learning</a></li>
																																<li><a href="https://fs.blog/reading/">Reading</a></li>
																																<li><a href="/smart-decisions/">Decision Making</a></li>
																																<li><a href="https://fs.blog/intellectual-giants/">Intellectual Giants</a></li>
																					</ul>
									</div>
				
				<div>
					<h4>Partner</h4>
											<ul>
																								<li><a href="/sponsorship">Sponsorship</a></li>
																																<li><a href="https://rethinkworkshops.com/">Workshops</a></li>
																					</ul>
									</div>
				<div>
					<h4>Connect</h4>
					<ul>
						<li><a href="https://www.facebook.com/FarnamStreet/"><i></i></a></li>
						<li><a href="https://twitter.com/shaneaparrish"><i></i></a></li>
						<li><a href="http://www.youtube.com/c/TheKnowledgeProject"><i></i></a></li>
						<li><a href="https://www.instagram.com/farnamstreet/"><i></i></a></li>
						<li><a href="/feed/"><i></i></a></li>
					</ul>
					<div>
						<div>
							<script src="https://forms.convertkit.com/325767?v=6"></script>

						</div>
					</div> 
				</div>
			</div>
		</div>
	</div> 
	<div>
		<div>
			<div>
				<p><i></i> 2020 Farnam Street Media Inc. All Rights Reserved.</p>
				<p>
					Hosted by <a href="https://pressable.com/">Pressable</a>. See our <a href="https://www.fs.blog/privacy-policy/">Privacy Policy.</a><br/>Farnam Street participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising commissions by linking to Amazon.
				</p>
			</div> 
			<div>
				<p>We're <a href="https://syruspartners.com/">Syrus Partners</a>. We buy amazing businesses.</p>
			</div> 
		</div>
	</div> 
</footer>
<script src="//z-na.amazon-adsystem.com/widgets/onejs?MarketPlace=US&amp;adInstanceId=33713fe9-c73f-4b3d-ba8d-436c0a0f0fd4"></script>
<script src="https://snip.ly/site/5a1350b576ae562762b24001.js"></script>

<script>(function(s,u,m,o,j,v){j=u.createElement(m);v=u.getElementsByTagName(m)[0];j.async=1;j.src=o;j.dataset.sumoSiteId='eab90499f89fe425f2d819895641b1a1772cbeb3d761fef0ceffe771f5ca585b';j.dataset.sumoPlatform='wordpress';v.parentNode.insertBefore(j,v)})(window,document,'script','//load.sumo.com/');</script>    <script>
      var ajaxurl = "https://fs.blog/wp-admin/admin-ajax.php";

      function sumo_add_woocommerce_coupon(code) {
        jQuery.post(ajaxurl, {
          action: 'sumo_add_woocommerce_coupon',
          code: code,
        });
      }

      function sumo_remove_woocommerce_coupon(code) {
        jQuery.post(ajaxurl, {
          action: 'sumo_remove_woocommerce_coupon',
          code: code,
        });
      }

      function sumo_get_woocommerce_cart_subtotal(callback) {
        jQuery.ajax({
          method: 'POST',
          url: ajaxurl,
          dataType: 'html',
          data: {
            action: 'sumo_get_woocommerce_cart_subtotal',
          },
          success: function(subtotal) {
            return callback(null, subtotal);
          },
          error: function(err) {
            return callback(err, 0);
          }
        });
      }
    </script>
    <script src="https://149366099.v2.pressablecdn.com/wp-content/themes/farnamstreet/js/nav.js?ver=5.4.2"></script>
<script src="https://149366099.v2.pressablecdn.com/wp-content/themes/farnamstreet/js/tabs.js?ver=20151215"></script>
<script src="https://c0.wp.com/c/5.4.2/wp-includes/js/wp-embed.min.js"></script>
		<script>
			(function() {
			var t   = document.createElement( 'script' );
			t.type  = 'text/javascript';
			t.async = true;
			t.id    = 'gauges-tracker';
			t.setAttribute( 'data-site-id', '5b2baf7fe5b7c935e5c6fedf' );
			t.src = '//secure.gaug.es/track.js';
			var s = document.getElementsByTagName( 'script' )[0];
			s.parentNode.insertBefore( t, s );
			})();
		</script>
		<script src="https://stats.wp.com/e-202026.js"></script>
<script>
	_stq = window._stq || [];
	_stq.push([ 'view', {v:'ext',j:'1:8.6.1',blog:'148761140',post:'20868',tz:'-4',srv:'fs.blog'} ]);
	_stq.push([ 'clickTrackerInit', '148761140', '20868' ]);
</script>



</body></html>

health

Health

problemsolving

Problem Solving

teamwork

Teamwork

leadershipandmanagement

Leadership & Management

softwareengineering

Software Engineering

The Three Essential Properties of the Engineering Mind-Set

<p><em>Engineers use a unique mode of thinking based on seeing everything as a system. They see structures that aren’t apparent to the layperson, they know how to design under constraints, and they understand trade-offs. </em><em>Adopting an engineering mindset can help you in any field. </em> </p><p>*** </p><p>In his book <a href="http://www.amazon.com/gp/product/039323987X/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&amp;camp=1789&amp;creative=9325&amp;creativeASIN=039323987X&amp;linkCode=as2&amp;tag=farnamstreet-20&amp;linkId=DVAFNEHYYJFDRJTI">Applied Minds: How Engineers Think </a>, Guru Madhavan explores the mental tools of engineers that allow engineering feats. His framework is built around a flexible intellectual tool kit called modular systems thinking. </p><p>The core of the engineering mind-set is what I call modular systems thinking. It’s not a singular talent, but a melange of techniques and principles. Systems-level thinking is more than just being systematic; rather, it’s about the understanding that in the ebb and flow of life, nothing is stationary and everything is linked. The relationships among the modules of a system give rise to a whole that cannot be understood by analyzing its constituent parts. </p>

<p><em>Engineers use a unique mode of thinking based on seeing everything as a system. They see structures that aren’t apparent to the layperson, they know how to design under constraints, and they understand trade-offs. </em><em>Adopting an engineering mindset can help you in any field. </em> </p><p>*** </p><p>In his book <a href="http://www.amazon.com/gp/product/039323987X/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&amp;camp=1789&amp;creative=9325&amp;creativeASIN=039323987X&amp;linkCode=as2&amp;tag=farnamstreet-20&amp;linkId=DVAFNEHYYJFDRJTI">Applied Minds: How Engineers Think </a>, Guru Madhavan explores the mental tools of engineers that allow engineering feats. His framework is built around a flexible intellectual tool kit called modular systems thinking. </p><p>Thinking in systems means that you can deconstruct (breaking down a larger system into its modules) and reconstruct (putting it back together). </p>

<p>There is no engineering method, so modular systems thinking varies with contexts. </p><p>Engineering Dubai’s Burj Khalifa is different from coding the Microsoft Office Suite. Whether used to conduct wind tunnel tests on World Cup soccer balls or to create a missile capable of hitting another missile midflight, engineering works in various ways. Even within a specific industry, techniques can differ. Engineering an artifact like a turbofan engine is different from assembling a megasystem like an aircraft, and by extension, a system of systems, such as the air traffic network. </p>

<p>There is no engineering method, so modular systems thinking varies with contexts. </p><p><strong>1. The ability to see a structure where there’s nothing apparent. </strong> </p><p>From haikus to high-rise buildings, our world relies on structures. Just as a talented composer “hears” a sound before it’s put down on a score, a good engineer is able to visualize—and produce—structures through a combination of rules, models, and instincts. The engineering mind gravitates to the piece of the iceberg underneath the water rather than its surface. It’s not only about what one sees; it’s also about the unseen. </p>

<p>A structured systems-level thinking process would consider how the elements of the system are linked in logic, in time, in sequence, and in function—and under what conditions they work and don’t work. A historian might apply this sort of structural logic decades after something has occurred, but an engineer needs to do this preemptively, whether with the finest details or top-level abstractions. This is one of the main reasons why engineers build models: so that they can have structured conversations based in reality. Critically, envisioning a structure involves having the wisdom to know when a structure is valuable, and when it isn’t. </p>

<p>[…] </p><p>Consider, for example, the following catechism by George Heilmeier—a former director of the U.S. Defense Advanced Research Projects Agency (DARPA), who also engineered the liquid crystal displays (LCDs) that are part of modern-day visual technologies. His approach to innovation is to employ a checklist-like template suitable for a project with well-defined goals and customers. </p>

<ul><li>What are you trying to do? Articulate your objectives using absolutely no jargon. </li><li>How is it done today, and what are the limits of current practice? </li><li>What’s new in your approach and why do you think it will be successful? </li><li>Who cares? If you’re successful, what difference will it make? </li><li>What are the risks and the payoffs? </li><li>How much will it cost? How long will it take? </li><li>What are the midterm and final “exams” to check for success? </li> </ul>

2. Adeptness at designing under constraints

<p>There is no engineering method, so modular systems thinking varies with contexts. </p><p><strong>1. The ability to see a structure where there’s nothing apparent. </strong> </p><p>This type of structure “helps ask the right questions in a logical way.” </p><p>The real world is full of constraints that make or break potential. </p><p>Given the innately practical nature of engineering, the pressures on it are far greater compared to other professions. Constraints—whether natural or human-made—don’t permit engineers to wait until all phenomena are fully understood and explained. Engineers are expected to produce the best possible results under the given conditions. Even if there are no constraints, good engineers know how to apply constraints to help achieve their goals. Time constraints on engineers fuel creativity and resourcefulness. Financial constraints and the blatant physical constraints hinging on the laws of nature are also common, coupled with an unpredictable constraint—namely, human behavior. </p>

<p>“Imagine if each new version of the Macintosh Operating System, or of Windows, was in fact a completely new operating system that began from scratch. It would bring personal computing to a halt,” Olivier de Week and his fellow researchers at the Massachusetts Institute of Technology point out. Engineers often augment their software products, incrementally addressing customer preferences and business necessities— which are nothing but constraints. “Changes that look easy at first frequently necessitate other changes, which in turn cause more change. . . . You have to find a way to keep the old thing going while creating something new.” The pressures are endless. </p>

<p>There is no engineering method, so modular systems thinking varies with contexts. </p><p><strong>1. The ability to see a structure where there’s nothing apparent. </strong> </p><p>This type of structure “helps ask the right questions in a logical way.” </p><p>The real world is full of constraints that make or break potential. </p><p>The ability to hold alternative ideas in your head and make considered judgments. </p>

<p>Engineers make design priorities and allocate resources by ferreting out the weak goals among stronger ones. For an airplane design, a typical trade-off could be to balance the demands of cost, weight, wingspan, and lavatory dimensions within the constraints of the given performance specifications. This type of selection pressure even trickles down to the question of whether passengers like the airplane they’re flying in. If constraints are like tightrope walking, then trade-offs are inescapable tugs-of-war among what’s available, what’s possible, what’s desirable, and what the limits are. </p>

<p>Mental models help us understand the world better, something which is especially valuable during times of confusion, like a pandemic. Here’s how to apply mental models to gain a more accurate picture of reality and keep a cool head. *** It feels overwhelming when the world changes rapidly, abruptly, and extensively. The changes come so […] </p>

<p>Our devotion to our values gets tested in the face of a true crisis. But it’s also an opportunity to reconnect, recommit, and sometimes, bake some bread. *** The recent outbreak of the coronavirus is impacting people all over the world — not just in terms of physical health, but financially, emotionally, and even socially. […] </p>

Chesterton’s Fence: A Lesson in Second Order Thinking

<p>A core component of making great decisions is understanding the rationale behind previous decisions. If we don’t understand how we got “here,” we run the risk of making things much worse. *** When we seek to intervene in any system created by someone, it’s not enough to view their decisions and choices simply as the […] </p>

The Three Essential Properties of the Engineering Mind-Set

GURU MADHAVAN

Thinking in Systems

Fundamental Properties of the Engineering Mind-Set

Simon I.'s ideas are part of this journey:

Related collections

Similar ideas