Modeling the corner blocks

I created a cube, changed the subdivision width, height and depth to 3. I selected the the edges inside the cube and scaled them all outward to the edges of the cube and I then added edges inside the cube using the edge loop tool. I then used the sculpt geometry tool on smooth to make the block irregularly shaped. I move the block to the corner of my building, rotated it so the long side was at the front of the building. I used duplicate special to create a stack of the blocks going up the building corner, and after deleting extra blocks I selected alternating blocks and after centering the pivot I rotated them 90 degrees and moved the blocks over so they aligned with the other blocks.