<a href="https://en.wikipedia.org/wiki/topology" class="extiw" title="w:topology">Topology</a> helps to think about the <a href="https://en.wikipedia.org/wiki/Twin_paradox" class="extiw" title="w:Twin paradox">w:Twin paradox</a> in the <a href="https://en.wikiversity.org/wiki/Special_relativity_and_steps_towards_general_relativity" class="extiw" title="wikiversity:Special relativity and steps towards general relativity">Wikiversity:Special relativity and steps towards general relativity</a> course. The "cut/paste" operation <i>g</i> is not yet shown in this image "0" of this series of images.
<a href="//commons.wikimedia.org/wiki/User:Boud" title="User:Boud">Boud</a>
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<span class="int-own-work" lang="en">Own work</span>