I would also like some clarification on this.

One of the most common occurrences of objects clipping into each other that I can find in many houses is with partitions and columns when setting up additional walls.
If you put the partition next to the column, there will often be an unsightly gap, but by clipping the partition into the column a little you eliminate the gap.


In my Large Private House I divided the upstairs room on the right into two spaces with partitions. But two partitions was not enough to reach across the entire space, so I had use a third one to complete the dividing wall. In order to execute this, the third partition is clipping into one of the other partitions.