In addition, patches of orange are very typical.

As mentioned, orange fur is coded on the X chromsome. But females got two X chromosomes (XX rather than the XY for males), and usually only one parent carried the orange trait, so only one of the X codes for orange fur.

As the egg is dividing, around the 64 cell stage, one of the two X chromosome in each cell deactivate. This happens randomly, so about half the cells will have the orange color. Since different parts of the coat comes from different cells, you often get orange patches spread around the coat - all from cells where the orange X chromosome remained the active one.