Origami Pencil Cup. If your paper is thick you’ll need to make the paper you use for the lower box a little shorter, 1 cm is what i took off. You can also just fold this over instead of cutting, which would actually make the raw edge of the side nice too.

Intersect by folding in half making a rectangle, making sure the color side is on the inside. Event registration is not possible anymore. Give it a crease, then unfold.