The Polybius Checkerboard Polybius was an ancient Greek writer who first proposed a method of substituting different two-digit numbers for each letter. The alphabet is written inside a 5–by–5 square matrix which has numbered rows and columns:
Martin Gardner
The Polybius Checkerboard Polybius was an ancient Greek writer who first proposed a method of substituting different two-digit numbers for each letter. The alphabet is written inside a 5–by–5 square matrix which has numbered rows and columns: