Logic puzzle simulator

12 balls and a scale

Three weighings, one odd ball. Explore the classic problem with a tactile, drag-and-drop layout that adapts to desktop and touch.

How to play
Blend strategy with deduction — the UI keeps every action visible.
  • Desktop: click a ball to select; click-and-drag to box-select.
  • Drag the selected balls onto the left or right scale.
  • Desktop: double-click a ball to mark it excluded (green).
  • Click "Weigh" to compare, then repeat up to three times.
  • Use "Undo" to revert the last weighing or "Clear scale" to reset placements.
  • When ready, enter your guess in the solution form.
Ball pool
Tap or drag to build your weighing groups.
Scale
Balance both sides for clearer answers.
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Weigh history
Every comparison is stored for quick backtracking.
What is the different ball?
Lock in your solution once you feel confident.