Just noticed in euclidean geometry, for any two line segments touching at a point there is exactly one triangle you can draw, i.e. a triangle is uniquely described by any two of its legs. In spherical geometry, there are two choices for the third leg!
Seems cool, but it’s currently missing some pretty important languages (Hindi, Urdu, Thai, Bosnian/Croatian/Serbian, Swahili, etc). I’d put up with something limited like this if it was FOSS and/or selfhostable but it appears not to be