D8 or D4 made from Polypanels

thingiverse

These dice are designed to be either a D4 or D8, depending on how you assemble them. They're not ideal for a D4 since the face-down side isn't visible, but you can create an eight-sided die with 1-4 appearing twice. Alternatively, you could build a D20, although I haven't included numbers above 8 yet. The original blank side is also included.