Flatten the cardboard box and cut out a large rectangular piece with scissors. Draw rounded edges on each corner, and cut out.
Paint one side of the cardboard with red acrylic paint, and leave to dry. Apply a second coat of paint, and when dry, flip it over and paint the reverse with two coats of silver paint.
Carefully cut a polystyrene ball in half with a kitchen knife (adult supervision required) and glue one half to the middle of the red side of the shield. Draw a square around the ball and paint with silver acrylic paint.
Download the motif templates and print onto A4 paper. Cut out, then draw around them on gold paper. Cut out, and stick the motifs around the silver square using the picture as a guide.
Cut a narrow strip of cardboard for a handle and cover with some silver duct tape. Stick to the middle of the silver side of the shield with more Duck Tape.