Using a marker, trace the outlines of the large and small templates on the foam core.
Cut out the shapes with a matte knife.
Paint the cacti green.
Score a line down the center of both cacti with the matte knife and fold.
Place small cactus in the fold and attach with T-pins and glue. Use a glue gun to secure T-pins into the foam base.
Starting in the center, create a vertical line design on the cacti with artist's tape in a shade of green different from the paint on the foam.
Add toothpicks to create cactus "needles," and use glue to secure them to the foam.
Hang prize bags for the Gold Rush Game on the toothpicks. Match the numbers on the prize bags to the numbers on the "gold nuggets" that kids will pan for.