Befunge-93 is an esoteric programming language where the program exists in a two-dimensional grid of cells, where each cell contains a single instruction, and execution can proceed in any cardinal direction across this grid — not just left-to-right, but also right-to-left, top-to-bottom, and bottom-to-top.
v < >?"/",^ >"\",^
bef in the Befunge-93 distribution
- bef (the reference implementation), an interpreter in ANSI C in the Befunge-93 distribution
- tc.catseye.yoob.befunge93, an interpreter in Java in the yoob distribution