How many movies have Kathleen Barr and William Anderson collaborated on?

They have worked on 4 movies together! Their first movie together was Mosaic (2007) while their highest rated movie together was My Little Pony: Equestria Girls - Rainbow Rocks (2014). They have not worked together since My Little Pony: Equestria Girls - Legend of Everfree (2016). They are most known for their animation films together.