Treasure Rocks

1 cup used coffee grounds
1/4 cup sand
1/2 cup salt
1 cup flour or more
1 cup water

Mix all ingredients and stir until dough-like. Shape into balls. Make a hole in the ball. Put a "treasure" into the hole, then fill the hole. Air dry for 2 days or 20 minutes in an oven preheated to 150 degrees F.

Break the rock open to find the treasure.