A crucial step in this project was creating the hole that the metal sculpture will use to enter the next room. This was new territory for me. I did my maths, marked the points, and started the cut by drilling out the four corner points of the triangle. We then cut into the cinder blocks from the bay side. I naively thought a standard cut off blade on a grinder would make short work of the cinder blocks. I've never seen abrasive disks get chewed up faster. Maybe a centimeter cut depth all around was made. But, it did give us a path of least resistance for the blocks to break on.
Once the four points were identified on the opposite side of the wall, we connected the dots, removed the drywall with a boxcutter, then used up more cutoff disks to score the cinder blocks on the gallery side.
a nine-pound sledge hammer later, we were through.