TAGGED
Math
4 designs tagged “Math”.

Board games / Dice
Go-first dice — four d12 that settle the whole turn order in one fair roll
Four twelve-sided dice carrying the numbers 1-48, one each. Everyone rolls once and reads the turn order straight off the table. Ties are impossible, and every one of the 24 finishing orders is exactly equally likely, so it does not matter which die a player picks up. Works for 2 and 3 players too by leaving dice in the bag. The numbering is a solved combinatorial object and the build refuses to export unless a brute-force check over all 20736 rolls still passes.

Toys & mechanisms / Mechanical
Wand Through the Wall — a Straight Wand Passes Through a Curved Slit
A dead-straight wand on a little turntable swings clean through two CURVED slits in a wall, twice per turn, without bending. The wand is skew to the axis, so it sweeps a hyperboloid; the wall cuts that in a hyperbola, and that is the slit. Four flat supportless parts, formula engraved on the base.

Jewelry & accessories / Earrings
Möbius Hoop Earrings — Twisted Ribbon, Prints Flat, No Supports
A hoop that is a real Möbius band: a 6 mm ribbon swept round a 30 mm circle, three half-twists. No supports.

Toys & mechanisms / Puzzles
Tower of Hanoi — Parametric Educational Stacking Puzzle
Classic recursion puzzle: move a graduated stack of discs across three pegs, one at a time, never a bigger disc on a smaller one. Parametric (n_discs 3–9, default 5); print each disc a different colour for a rainbow set and the base in wood-fill PLA for the grain shown. Kid-safe: smallest disc above the choke gauge, every edge filleted. Prints flat, no supports.