Summarize this article in one sentence.
This recipe is great for making washable sidewalk paint. It is not recommended for furniture or DIY chalkboards. If you can't find cornstarch, look for cornflour instead (but not cornmeal). You will need a little less than ¼ cup (60 milliliters) of water. Stir the two together with a whisk until the cornstarch dissolves. Do not over-mix, however, or the cornstarch will start to turn solid. If you can drizzle the cornstarch water from your whisk, you're ready for the next step. You can use either the liquid kind or the gel kind. You can also use liquid watercolor instead. How much you add is completely up to you. The more you add, the darker, deeper the color will be. Start with a few drops, and see how you like it. Dip a paintbrush into the paint, then paint designs onto your sidewalk or driveway. Let it dry and admire your work. When you are done, simply wash it away with water. Although this paint is washable, it can stain light surfaces. Be careful!

Summary:
Place 6 tablespoons (45  grams) of cornstarch into a bowl. Slowly stir in some cold water into the cornstarch. Stir in some food coloring. Use the paint.