Fourth Class designed and built their own traffic lights. We covered the bottom and sides of the tissue box with black paper. We left the top uncovered, in order to insert the electrical parts in from the back. We drew and cut out 3 circles, approximately 6 cms in diameter. We cut 3 different colours of cellophane to fit over the holes. We glued them over the holes in the correct order. Then we put the 3 bulbs in the bulb-holders, connected them in a line using crocodile leads and attached them to the tissue box so that each bulb was opposite a hole with cellophane. We connected the free ends of the crocodile leads to the battery.