The Sphinx
Not sure how I stumbled across it, but Jim Storer had this info about an antiique puzzle called The Sphinx, a dissection of an equilateral triangle into a rectangle. It came packed tight in the box, and you were supposed to make the triangle.
https://www.cs.brandeis.edu/~storer/JimPuzzles/ZPAGES/zzzRichter15-Sphinx.html (Does contain spoilers for the solution.)
Click a nonsymmetric shape to flip it. Solid points translate, open points rotate.
