🧱 ShapeStack is a set of chunky, stackable learning blocks that interlock into wobbly towers — and teach while kids play. Each block is a rounded shape with a character raised on top that nests into the engraved base of the next block, so the whole stack clicks together as it grows. Stack them in order, sort them by shape, or build silly mixed-up towers.

Comes ready to print in three sets, with more you can invent yourself:

🔢 Numbers (0–10) — each numeral on a different shape, and each block also carries a dice-style dot count on its side faces, so children connect the symbol to the quantity as they count and stack.
🐶 Animals (Dog · Cat · Mouse · Cheese) — a playful little stack with friendly raised faces and the animal's name engraved on the side.
⬟ Shapes (square, triangle, pentagon, hexagon, circle, star) — each block shows its own geometric symbol for early shape recognition.

🎨 Make it your own — everything is customizable
ShapeStack is fully parametric in OpenSCAD (and on MakerWorld's Parametric Model Maker). You can change:

• Shape — 14 options: triangle, square, pentagon, hexagon, heptagon, octagon, nonagon, decagon, circle, star, plus four card suits (spade, club, heart, diamond)
• Size — width 40–150 mm and height 10–20 mm
• Top character — raised, and it's what interlocks with the block above
• Bottom character — engraved, receives the block below
• Two lines of side text — one word on the alternating faces, a second word/symbol on the faces in between (letters, numbers, dots, or emoji)
• Colour — per block
• Three independent fonts — mix text and emoji on different faces of the same block
• Edge rounding, bevel size, engraving depth, and stacking tolerance — tune the fit and feel

That means you can print any letters, numbers, words, names, or symbols — spell a child's name, build the alphabet, make a counting set in your own colours, or a deck-of-cards stack.

📦 What's included

• 6 ready-to-print profiles (.3mf) — Numbers, Animals and Shapes, each in a multi-colour (AMS) and a single-colour (no-AMS) version
• 21 individual STLs — every number, animal and shape, ready to slice
• Full open-source project (.zip) — the OpenSCAD source, a presets.json of all the ready-made blocks

♿ Designed to be inclusive
The large, tactile, customizable design adapts easily for children who need extra support. Characters are raised on top and engraved on the sides, so they can be seen and traced by touch; the predictable interlocking and chunky size suit fine-motor practice and calming, repetitive play; and you can print high-contrast colours or oversized glyphs on request. (ShapeStack is a play-and-learning toy, not a medical or therapy device.)

✅ Safe & kid-friendly by design

• Rounded edges throughout — no sharp corners
• Large blocks printed as single pieces — no small detachable parts
• Best for ages 2–6, and safe from around 18 months with supervision
• As with any PLA print, it's a toy, not a teether — supervise young children

🖨️ Printing
No supports, no glue, no assembly. Print each block in a different filament for a bright rainbow stack; AMS profiles add multi-colour faces, but the single-colour versions look great too. If blocks fit too tight or too loose, nudge the stacking tolerance parameter.

Free for parents, kids, teachers and therapists to print, share and adapt.

🎈 Made for the Children's Toy Design Contest — celebrating imagination, curiosity, and the joy of play.