Lemons Are Not Red by Laura Vaccaro Seeger

I've read a number of 'color' books. The ones where they use either 1) a storyline or 2) no storyline to teach colors to young children. Nothing seemed to help my youngest get interested in colors...until this book. 

Lemons are Not Red uses the classic 'give them the wrong info and let them choose the right info' tactic. Look at the title.

"Lemons are not red. Lemns are yellow. Apples are red."

Nothing radical, right? But the way the book is put together, children see through cut-outs at a red lemon; Then turn the page and the lemon is now yellow, with a correctly colored apple on the opposing side.