Crayon Art! Very cool. Tape off the white with Painter's tape. Then after melting crayons, place stencil over bottom, mark with toothpick/chalk and then paint black acrylic paint once stencil is removed.
My own efforts at melted crayon art for our daughter... Board is the normal backing to the picture frame. Painted with white chalk paint. Letter and umbrella blanks cut out of cardboard and the rest is obvious from the pics.