A short history of hiding letters
Grid & Symbol Ciphers Through History
Before machines, secrecy was a matter of geometry. Ancient Greek signallers turned each letter into a pair of numbers so a message could travel by torchlight across valleys. Two thousand years later, Freemasons replaced numbers with shapes, writing whole letters as fragments of a grid. Both ideas share one trick: put the alphabet in a box, then describe the box instead of the letter.
Polybius Square
Letters become coordinates in a 5×5 grid. Encode and decode live.
Open the square →Freemasons eraPigpen Cipher
Letters become the walls around them. Type a word, read it as symbols.
Open the key →Compare both ciphers
| Polybius Square | Pigpen Cipher | |
|---|---|---|
| Era | c. 150 BCE, Ancient Greece | 18th century, Freemason lodges |
| Type | Numeric substitution | Symbolic substitution |
| Structure | One 5×5 grid, I/J shared | Two 3×3 grids + two X grids |
| Output | Pairs of digits (11–55) | Line fragments, some with a dot |
| Use case | Long-distance torch signalling, telegraphy | Private records, gravestones, ritual notes |