ID X and Y

X created Y in 1939 as an assignment for the retailing company. The retailer had been buying and giving away coloring books  every year and it was decided that creating their own book would save money. 2.4 million copies of Y were distributed by the company in its first year. Because X had created Y as an employee, he did not own the license.

In a BBC animation, Y is never mentioned by name and references are replaced by a character interrupting with the phrase "Dont say that name!" or something similar, preumably for copyright reasons.

Edit: Changed X to Y in the second para