White glue and food coloring OR bubble paint
Mirror, or plastic wrap taped down on a piece of Cardboard. (This is what you will be "Drawing" on.
This is a super Easy project to do with the kids.
Allow your child to draw a picture with the paints. My girls LOVE making penguins. Allow to dry for 4-6 hours. Peal from mirror or plastic wrap and TA-DA...Window clings. They work awesome!
With white glue and food coloring.
In several plastic or paper cups, mix 1/4 (ish) cups of white glue with a few drops of food coloring. Make several different colors. Using a toothpick, a paintbrush, or a plastic spoon, create your artwork. Allow to dry overnight (8 hours), and then peel and stick to your window.