Here's a recipe I found. Enjoy!
Sand Art Brownies Submitted by: Janet
Mix ingredients in a wide mouth quart size jar, just like sand art that kids make today.

Ingredients: CookieRecipe.com
recommends:

5/8 cup all-purpose flour
3/4 teaspoon salt
1/3 cup unsweetened cocoa powder
1/2 cup all-purpose flour
2/3 cup brown sugar
2/3 cup white sugar
1/2 cup semisweet chocolate chips
1/2 cup vanilla chips
1/2 cup walnuts

1 Mix the 5/8 cup of flour with salt. In a clean wide mouth quart or liter sized jar layer the ingredients in the order given. Starting with the flour and salt mixture and ending with the walnuts.
2 Attach a decorative tag to the out side of the jar with the following directions.

Sand Art Brownies
1. Preheat oven to 350 degrees F (175 degrees C). Grease one 9x9 inch square baking pan.
2. Pour the contents of the jar into a large bowl and mix well.
3. Stir in 1 teaspoon vanilla, 2/3 cup vegetable oil and 3 eggs. Beat until just combined.
4. Pour the batter into the prepared pan and bake at 350 degrees F (175 degrees C) for 25 to 30 minutes. Enjoy!
Makes 1 -9x9 inch pan