Solutions to the <a href="https://en.wikipedia.org/wiki/Opaque_forest_problem" class="extiw" title="en:Opaque forest problem">opaque forest problem</a> for a unit circle. Left: The shortest possible connected solution, with total length <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 2+\pi }"><semantics><mrow class="MJX-TeXAtom-ORD"><mstyle displaystyle="true" scriptlevel="0"><mn>2</mn><mo>+</mo><mi>π<!-- π --></mi></mstyle></mrow><annotation encoding="application/x-tex">{\displaystyle 2+\pi }</annotation></semantics></math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/37f72b2cc2703e69e7bebc8b950797c9af5850b8" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.505ex; width:5.335ex; height:2.343ex;" alt="{\displaystyle 2+\pi }"></span>. Right: The shortest known solution when connectedness is not required, with total length approxiately 4.7998.
<a href="//commons.wikimedia.org/wiki/User:David_Eppstein" class="mw-redirect" title="User:David Eppstein">David Eppstein</a>
<span class="int-own-work" lang="en">Own work</span>