Open out one of the paper-clips so it is straight. Then bend it to form the shape of a handle with a long shaft. Push the shaft through the two holes in the matchbox.

Carefully cut a small notch in the middle of each spent match, and tape a match to each end of the ruler with the notch facing out.

Tape the ruler over the top of the tin, making sure that one end of it sticks out about 2.5cm over the top of the matchbox.