how is the mental block made?
i know it is a skewb variation, but that is all i know

A mental block is just a buildup on the skewb. If you would use a keychain skewb you can make from it a mental block that is not that large.

i know that it is a buildup, but what pieces are built up... i cannot see which are built to look like mental block

The center square on the largest surface is a square piece on a skewb. So that makes all the corners build ups of squares, and all the edges buildups of triangles. A very challenging modification.