A self-contained, offline logic puzzle: pupils reorder ten counters 1–10 using prefix reversals, building problem-solving and pattern-spotting skills.

Reverser is based on the “pancake sorting” problem: a well-known puzzle in computer science where a stack can only be rearranged by flipping sections from the top down. Here, pupils click any counter to reverse everything from the start of the row up to and including it, and must work out a sequence of these moves to sort the whole row into order 1–10 in as few moves as possible.

It’s a satisfying standalone starter, plenary, or “finish early” task, and doubles as an accessible entry point into computational and algorithmic thinking — the same flip-based sorting idea turns up in real computer science. No prior knowledge is needed to play, but there’s genuine depth for pupils who want to hunt for the optimal strategy.

Features:
Built-in optimal solver: an unlimited-use Hint button reveals the mathematically best next move at any point, and the Target figure shown for each puzzle is the true minimum number of moves — not an estimate.
Try Again button to replay the exact same shuffle and try to beat your move count, alongside New Game for a fresh one.
Optional rotation animation showing the physical “flip” as counters sweep round together, with an adjustable speed control (and it respects reduced-motion accessibility settings, falling back to an instant move).
Clean, classroom-friendly on-screen design with clear visual feedback for counters already in the correct place.

Installation
Runs entirely offline, in-browser, with no installation, no accounts, and no pupil data ever collected or uploaded — fully GDPR-compliant. Works on interactive whiteboards, laptops, and tablets alike. Suitable across KS3 and KS4 as a logic/reasoning activity, and equally at home in a maths club, computing club, or as extension material for quick finishers.

See the included Setup & Troubleshooting Guide for how to open the file on school devices.