Thanks everyone.
Orangeman, the font is Arial Rounded Bold.the backer is 1/4" plywood. I painted the backer before gluing the two layers together. I colored the backing to match the letters to help him learn colors. He says green and yellow so maybe this will help with other colors.
DW, ahh, good idea. I'm sure I'll be making more and will add the finger hole. Thanks for the tip.