Slab

The slab was one of the first blocks added into World Builder based off of its ID, appearing during the Testing phase of its existence. It was added when 2x2 resizing was not a thing, though Grim is unable to remove it because it would break worlds using the block.

Uses

Nowadays, slab is used to achieve smaller grid sizes when resized with 1x1, and since it is a half block it will be able to achieve 0.5x0.5 in a way.