Super Why! (found stop-motion Nick Jr. pilot of PBS Kids CGI animated series; 1999)

Screenshots from the pliot

Super Why! is an animated television show about a kid who jumps into books. The show is created by Blue's Clues creator Angela Santomero in 1999, and a pilot was created for Nick Jr. by Cuppa Coffee Animation in Toronto, Canada.

What makes the pilot different from the final show is that this pilot was animated in stop-motion animation instead of CGI animation, and all the characters looked different from the final pilot. A revised version finally aired on PBS Kids in 2007.

Sources

http://kidscreen.com/1999/07/01/25954-19990701/

http://www.alexandergorelick.com/work-history.html