12 x 18 sheet--1/2 chocolate, 1/2 rainbow (took parts of the batter and dyed in red, orange, blue, green--got the idea from here (cant remember exact person, but thanks!!). I was given control of the outcome, but was requested to make the rainbow & the yellow brick road. I even put little red slippers under Dorothy's picture (cupcake pic). THe cake was a hit with the 2 sisters sharing a birthday!