One two one eraser

The eraser is designed to be a hollow cylinder similar in length to the pencil, and the hollow part can accommodate a pencill. When the eraser is still very long, we will think that it is suitable for stuffing a short pencil inside, so that it can be attached to the eraser for continued use. When we continue to use the eraser and shorten it, that it becomes too short for a pencil to attach to it, it seems that it can only be attached to a long pencil, so that it will not be easily forgotten or discarded by us. This allows both to be fully utilized and interesting.