There is no such word as "masonary". The correct spelling should be masonry: m-a-s-o-n-r-y ; no second "a".
Near the end of the episode, Fred is in the water while Betty, Bamm Bamm, Barney, Wilma, and Pebbles are standing on a bridge above. If you watch closely, there is a frame or two where Bamm Bamm's hair is red, like Pebbles' rather than white as it should be.