I'm new to Godot and I'd like to make a game with 2d isometric graphics. There are lots of tutorials on using tilesets, but every one I've seen so far uses one image per one tile (even if they're put together in one large spritesheet) like so:

This is problematic if I want to have lots of variation in my base shape, like different egdes and corners and so on. What I'd like to achieve is to have to draw just parts of the blocks and put them together to form a tile in the editor, like so:

This way I only need to modify the specific sub-tiles if i want to change, for example, the look of grass on top, and it will propagate to all tiles with grass on top. I know about tile patterns in Godot, but they seem to be something else. I want to take the triangular patches from my spritesheet and compose the tiles out of them. Is it possible in Godot?