UPDATE: Version with improved hinges: https://www.thingiverse.com/thing:3510716

Hinged triangle-square dissection (Dudeney's dissection). I used an X-acto knife to clean away stray filament from near the hinges before attempting to bend them.

I tried printing this model https://www.thingiverse.com/thing:263152, but the hinges did not print successfully with my printer, so I designed my own version.

Geometry for the dissection from: http://www.gavin-theobald.uk/HTML/Triangle.html

Idea for hinge from: https://www.instructables.com/id/Perfect-3d-Printed-Hinge/