List of impossible puzzles

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This is a list of

• 15 Puzzle
  – Slide fifteen numbered tiles into numerical order. Impossible for half of the starting positions.
• Five room puzzle
  – Cross each wall of a diagram exactly once with a continuous line.
• MU puzzle – Transform the string MI to MU according to a set of rules.
• Mutilated chessboard problem – Place 31 dominoes of size 2×1 on a chessboard with two opposite corners removed.
• Coloring the edges of the Petersen graph with three colors.
• Seven Bridges of Königsberg – Walk through a city while crossing each of seven bridges exactly once.
• compass and straightedge
• Three cups problem – Turn three cups right-side up after starting with one wrong and turning two at a time.
• Three utilities problem – Connect three cottages to gas, water, and electricity without crossing lines.
• Thirty-six officers problem
  – Arrange six regiments consisting of six officers each of different ranks in a 6 × 6 square so that no rank or regiment is repeated in any row or column.

See also

• Impossible Puzzle
  , or "Sum and Product Puzzle", which is not impossible
• word puzzle
• List of undecidable problems, no algorithm can exist to answer a yes–no question about the input