Aceto is an esoteric programming language made by L3viathan, designed according to the wishes of @sarnthil. The name has no meaning other than being a reference to OIL. It is a stack-based language where the pointer moves on a simulated Hilbert curve.
An Aceto program is a square text file. If the file does not look like a square (with side length 2^n for some n), it gets filled with spaces to the right and top (!) until it is. The pointer then starts at position 0,0 (which is the bottom left!) and from then on follows the path of a Hilbert curve to read instructions.
Aceto has an infinite tape in each of which is a stack. The program starts with one of these stacks as the active stack.
An official implementation as well as a more in-depth description of the language can be found here.
pdcpcpdc p3+4-3+p dc*8*73d +dcpd3+c 4-3dpcdp pc*+8--3 9*48pcIc 8dcp48*p