Look at the results from the dads NOT being split to Purple, and of the sons, expect 50% to be visual for Purple, and 50% of the daughters being visual for Purple.
:-)
IB dad X Purple mom =
all sons IB split to Purple
all daughters IB
IB Pied dad X Purple mom =
50% sons IB split to Purple and White, 50% sons IB split to Purple and Pied
50% daughters IB split to White, and 50% daughters IB split to Pied
:-)