All three types of column are present in the visual cortex of humans and macaques, among other animals. In macaques, it was found that both blobs and pinwheel centers tend to lie in the center of ocular dominance columns, but no particular relation has been found between pinwheel centers and blobs. In humans, the layout of the columns is similar; however, humans have somewhat variable column expression with at least one subject having disordered columns similar to those commonly found in squirrel monkeys.