School Bus Yellow 100 Foot Plastic Table Roll Go to an office supply store and buy a roll of yellow bulletin board paper. Use white masking tape for the moarter between the bricks. Or, a cheap yellow sheet (flat). Or, construction paper (yellow). You can build an "Emerald City" backdrop out of various sized cardboard boxes painted green. Ask others to pitch in their empty cereal or pasta boxes, furnature stores often have really large boxes.