The idea is from a Minecraft mod, MCPatcher. It has a feature called CTM, which allows you to create outlined tile textures using 47 sprites.

I implemented it in Pico-8 (though it's barely optimized) and made this example cart, which dynamically generates connected textures.
Arrow keys to move cursor, O
to place a tile, X
to erase.
[Please log in to post a comment]