Mix the 5/8 cup of flour with salt. In a clean, wide mouth 1 quart or 1 liter jar, layer the ingredients in the order given. Starting with the flour and salt mixture, and ending with the walnuts.
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 in the preheated oven for 25 to 30 minutes.