Pour the water into a medium saucepan. Sprinkle the gelatin over the water. Let stand 1 minute.
With adult help, bring the mixture to boiling, stirring constantly until gelatin dissolves. Remove from heat.
Stir in frozen juice concentrate. Stir until concentrate is melted. if deeper color is desired, stir in food coloring.
Pour mixture into a foil-lined 8x8x2-inch baking pan. Cover and chill until firm.
Uncover and turn the pan upside down onto a piece of foil sprayed with nonstick coating. Use cookie cutters or a table knife to cut the gelatin into shapes. Create towers of gelatin -- if you're in a building mood -- or eat them now. Makes about 36 (1-1/2-inch) gelatin pieces.