When placing a painting, it only expands up and to the right, instead of taking advantage of the rest of the space it has to expand. For example, make a 2x2 wall. Then try to place a painting of the size 2x2 anywhere but the bottom left block. The painting will not place because it is trying to go up and to the right instead of looking to see if there is blocks to the left and bottom. This also ruins painting randomization. If you place a random painting on the top right of the 2x2 wall, it will always be a 1x1 painting. If you place a painting on the bottom right of the 2x2 wall, it will always be a 2x1 painting. If you place a painting on the top left of the 2x2 wall, it will always be a 1x2 painting.