Claw Compiler

Drive a warehouse crane with code, restacking coloured crates under a move limit tight enough to demand recursion.

How to play

Build a program from crane instructions — move left and right, grab, drop and colour conditions — to rearrange the bins of crates into the target stack. The instruction limit is deliberately tight, so you'll lean on the Call command, which re-runs your whole program from the top; a condition that fails becomes the base case that stops the recursion.

• Add crane instructions from the palette to your program
• Use IF-held and IF-top colour conditions to branch
• Use Call to re-run the program from the top as a recursive loop
• Match the target arrangement within the instruction limit

Controls

• Desktop: click palette instructions, drag chips to reorder, click Run to execute
• Phone & tablet: tap instructions and the Run button

Tips & strategy

• Think in terms of one repeatable step plus a stop condition — that's your recursive routine
• Let a failing colour condition act as the base case so the crane knows when to halt
• Step through a run to see exactly where the crane grabs the wrong crate

What you'll learn

Claw Compiler teaches recursion through a crate-stacking crane and a strict move budget, making a hard idea concrete.

• Skills: recursion, problem decomposition, programming logic
• Best for: roughly grades 8–12 (ages 13+)
• For parents & teachers: makes recursion concrete and intuitive.

About Claw Compiler

Claw Compiler is an original programming puzzle that teaches recursion through a crate-stacking crane and a strict move budget. Play free in your browser with daily and practice levels.

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