Stacking Numbers 1–10 – Counting Puzzle Tray

A tactile counting puzzle: every number N is exactly N units tall, so kids can see – and feel – that 10 is ten times as tall as 1. All pieces fit snugly into the tray: 1 + 1 + 2 + … + 9 and the double-width 10 fill the 6 × 11 grid completely. How it works - Every digit has the same width; its height is N × one unit (17 mm).

- Digits are built from a constant-width stroke – taller numbers only get longer straight sections, curves and hooks stay the same, so even the 9 and 10 stay crisp and readable.

- The pairs 2 + 9, 3 + 8, 4 + 7, 5 + 6 and 1 + 1 + 10 each fill one column – a nice "make 11" game on its own.

Print settings (tested on Bambu Lab A1, PLA) - 0.2 mm layer height, 3 walls, 15–20 % infill, no supports

- Pieces print flat (6 mm thick), tray 155 × 192 × 9 mm

- Keep elephant-foot compensation on (0.15 mm)

Colors 3 piece colors + tray = 4 filaments. No multi-material unit? Every piece is single-color, so just print one plate per color. - Red: 3, 7, 10

- Yellow: 1, 2, 5, 8

- Blue: 1, 4, 6, 9

- Tray: white

No two neighbouring pieces in the tray share a color. Fit Pieces have a 0.1 mm gap between each other and 0.15 mm to the tray wall, so the full set sits snugly without rattling. Tip: to empty a full tray, simply turn it upside down. About Designed from scratch as a parametric model (Python / build123d). Inspired by a stacking-numbers toy I saw online.