Author: Urs Format: MarkdownItexreplaced the gif-illustration of a tetrahedron with `tikzpicture`-code
<a href="https://ncatlab.org/nlab/revision/diff/tetrahedron/7">diff</a>, <a href="https://ncatlab.org/nlab/revision/tetrahedron/7">v7</a>, <a href="https://ncatlab.org/nlab/show/tetrahedron">current</a>
replaced the gif-illustration of a tetrahedron with tikzpicture-code