1/4 cup cornstarch
1/4 cup cold water
6 to 8 drops food coloring
Mix cornstarch and cold water together in a small plastic bowl. Add food coloring and stir. Repeat this process to create different colors of sidewalk paint.
Use sidewalk paint for painting large areas, such as hopscotch grids, make-believe roads and highways, etc. When done, you can wash it away with the garden hose.