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How Grid-Based Program Flow Works
Learn how a pointer moving across a two-dimensional grid replaces the top-to-bottom reading of ordinary code, and how turns, loops and branches emerge from layout.
The Funge Family
Grid Program Flow
How a pointer moving through a grid replaces linear code.
Dead Code and Unreachable Cells
Find out what unreachable cells are in a grid program, why a pointer may never visit them, and how programmers use those cells to store data.
Drawing Program Flow as Paths
Sketching the route a pointer takes through a grid helps you plan, check and document a program. Here is a practical way to draw and annotate flow paths.
Instruction Pointer Direction and Turning
How the instruction pointer's four directions, arrow cells and conditional turns work in grid languages, and how turning replaces the usual if statement.
Loops Formed by Grid Geometry
See how the shape of a pointer's path creates repetition in a grid program, from a ring of four arrows to a counting loop with a single exit.
Self-Modifying Code on a Grid
Grid programs can read and write cells of their own playfield. Learn how self-modifying code works, with a small example, and why it makes programs hard to read.
Wrapping Edges and Toroidal Space
What happens when a pointer leaves the edge of a grid? Learn how wrap-around works, why it forms a torus, and how it shapes the layout of grid programs.
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