Proof of concept for Marching Squares autotiling in fusion. Unfinished in the sense that I haven't implemented array saving, but it goes through the process.
currently has three example brushes, the default marching squares tileset(right arrow), the terrain(down arrow) and a foliage sihouetteleft and up arrows.MarchingSquaresBrush.mfa
Run the file, use the left mouse to draw empty space and the right mouse to draw tiles. use the arrow keys to switch between tilesets.
press the 1 key for default blocky view. press the 2 key for marching squares view.
Enjoy, and let me know if I've missed anything.