Use a round cookie cutter to cut a circle from each piece of bread and the ham. Try to cut the circles as close to the edges as possible so that you have plenty of extra bread and ham left.
Cut 6 triangles from the remaining bread, and one triangle from the ham. Cut a small circle from the remaining ham for the nose.
Cut 3 large slices of skin from the side of the cucumber. Using one of the bread triangles as a guide, cut two triangles from the cucumber skin.
Using a small circle cutter, cut a crescent moon shape from the remaining cucumber skin for the mouth. Cut two tiny circles for the eyes.
Cut 3 small circles from the carrot slices.
Assemble your sandwich - spread the two circles of bread with butter or spread and sandwich together with the circle of ham. Sandwich the bread triangles together in pairs.
Top one of the bread triangles with the ham triangle, and the other two with the cucumber triangles.
Arrange the sandwich in the bento box to form Colly Wobble's head, with the ham triangle on the top and two cucumber triangles on the sides.
Pop a carrot circle at the top end of each triangle.
Add the ham nose and cucumber crescent mouth. Add two cereal hoops for the eyes, finishing by popping a tiny cucumber circle in the middle of each cereal hoop.