proofs without words

• Tiling a Chessboard with Dominoes (Opposite Colors Removed)
  November 18, 2011
• N Choose 2 is the Sum of the First N-1 Integers
  October 2, 2011
• Möbius Transformations are Isometries of a Sphere
  July 23, 2011
• False Proof—31.5 = 32.5
  July 7, 2011
• Geometric Series with Geometric Proofs
  July 5, 2011