In the world of multi material 3D printing purge blocks are seen as at worst a necessary evil but we are a community. We must be able to come up with a shape that would print a purge block in a shape that would interlock.
I know some have discussed printing a Lego shape on the top but 3D printing means you can make any shape If we could establish a standard interlock shape something simple like a Dovetail in woodwork. If we build to a standard that has a height that’s always a multiple of mm or half mm increments.
We could have standard shapes as walls and corners.
The one thing we would need is a standard interlock shape and personally like the idea of a Male/Female dovetail side.