Drop Diagonal Block Step
From PMDOWiki
The Drop Diagonal Block Step is a floor generation step. Its typical priority is 3.2.
Usage
If the specified tile has two blocks that are touching diagonally but not in any other direction, then the two possible blobs of tiles are merged together.
Fields
This step has the following fields.
Terrain
The type of terrain that will be merged if blocks touch diagonally.
