cwinge

Top: in Super Mario Galaxy 2, the walls of Whomp's Fortress as depicted in the Throwback Galaxy have visible individual bricks as a visual detail.

Bottom: curiously, moving the camera into the fortress and seeing the wall from inside reveals that every single brick is actually fully modeled from all sides, despite only being seen from one side (and very slightly sticking out of the wall).

The reason for this is that due to the bricks being simple hexahedra, they only use 12 polygons each (2 per face). Due to the slight jutting out of the bricks, optimizing the model would mean shortening 4 of the faces (which does not reduce the number of polygons needed for that side), and removing one, saving merely 2 polygons.

The Wii hardware is more than capable of handling this small amount of extraneous polygons, and the advantage of keeping the bricks fully modeled is that the level designers were able to simply reuse the same model over and over by rotating it instead of needing to shorten it differently based on its orientation.

Source: noclip.website