Bricard octahedron
... that a Bricard octahedron can change its shape without changing the shapes of its faces?
... that a <b id="mwA5g"><a href="./Bricard_octahedron" id="mwA5k" rel="mw:WikiLink" title="Bricard octahedron">Bricard octahedron</a></b> <i id="mwA5o">(pictured)</i> can change its shape without changing the shapes of its faces?