Geometry

The Semaphore cipher is a visual signaling system that encodes letters as distinct physical positions rather than transforming text through mathematical substitution. Although often grouped with ciphers for convenience, Semaphore is more accurately described as a manual encoding system, where meaning is conveyed by the position of flags, arms, or mechanical indicators.

The Spiral cipher is a classical transposition cipher that arranges plaintext letters into a grid or spiral pattern, then reads them off in a predetermined order to produce ciphertext. It is a variant of route ciphers, where the sequence of reading the letters is the key. While the exact origin is unclear, spiral and route-based ciphers were explored in Europe during the 16th and 17th centuries for military and diplomatic correspondence, combining simple letter rearrangement with a concealed reading path.

The Map Cipher is a simple substitution cipher that encodes messages using a geographic or visual reference, often overlaying a plaintext message onto a map and extracting letters based on pre-defined coordinates or zones. Each plaintext letter is mapped to a position on the map, and the corresponding symbol, letter, or code from that location becomes the ciphertext. This type of cipher combines geographic knowledge with substitution to obscure the message.

The Keyboard Code is a playful substitution cipher that maps letters to other keys based on their positions on a standard QWERTY keyboard. Instead of using numerical shifts like the Caesar Cipher or keyword sequences like the Kangaroo Cipher, this cipher substitutes each letter according to a physical adjacency or pattern on the keyboard layout.