The Minkowski sum of two identical squares is a square whose edge is the double of the original edges.
<a href="//commons.wikimedia.org/wiki/User:Smedlib" title="User:Smedlib">Smedlib</a>, based on work by <a href="//commons.wikimedia.org/wiki/User:Luke_Antony" class="mw-redirect" title="User:Luke Antony">Luke Antony</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>