<a href="https://en.wikipedia.org/wiki/Frenet-Serret" class="extiw" title="w:Frenet-Serret">Frenet-Serret</a>-frame moving along a Helix around a <a href="https://en.wikipedia.org/wiki/torus" class="extiw" title="w:torus">torus</a>.
<ul><li><span style="color:#0000FF;">T</span> <a href="https://en.wikipedia.org/wiki/tangent_vector" class="extiw" title="w:tangent vector">tangent unit vector</a></li>
<li><span style="color:#00AA00;">N</span> <a href="https://en.wikipedia.org/wiki/normal_vector" class="extiw" title="w:normal vector">normal unit vector</a></li>
<li><span style="color:#FF0000;">B</span> is the binormal unit vector (<a href="https://en.wikipedia.org/wiki/cross_product" class="extiw" title="w:cross product">cross product</a> of T and N)</li></ul>
<a href="//commons.wikimedia.org/wiki/User:Rectas" title="User:Rectas">Rectas</a>
2018-06-12
<span class="int-own-work" lang="en">Own work</span>