Cateogirws.

Cateogirws. (pronounced catgirls) is a 2D esoteric programming language made by User:Dragoneater67 in 2026. It was partially inspired by pgmpiet.

Overview

The program is an image in the PGM file format representing a cyclic grid of instructions. Each instruction is represented by the value of a pixel mod 4 (which means that max value must be greater than or equal to 4). There is a program counter and a queue of bits. The program counter initially faces right and is located at the top-left corner of the grid. At each step, the program counter executes the instruction at its location, then goes 1 step in its direction.

Cateogirws. instruction table

Instruction	Description
0	Do nothing.
1	Enqueue 1.
2	Enqueue 0.
3	Dequeue a bit and rotate the program counter $90\times {\text{bit}}$° clockwise.

Computational class

Cateogirws. is Turing complete since it can simulate a cyclic tag system. Here is the method for that:

• Numerical opcodes would be used. Queue is simulated with 0 represented as two zeroes and 1 as eight ones, and each bit being followed by 8 ones.
• Program starts with:

2(Initial Data encoded)3
(List of 0's)          0
(List of 0's)          0
(List of 0's)          3

• Each production other than the last one is encoded as:

03(List of 0's when needed)              300330
30(Encoded production if not empty)      033003
33(List of 0's)                          333333
(List of 0's)

• Last production is encoded as:

03(List of 0's when needed)              30030
30(Encoded production if not empty)      03303
33(List of 0's)                          33330
(List of 0's)                                3

External resources

• Codeberg repository