This is the Cube, a recommended textbook from SapiX. It involves cutting a cube from various directions, allowing you to learn with your eyes and hands while examining the shapes of the cross-sections and the relationship between the cuts and the unfolded diagrams. It helps develop the ability to tackle solid geometry problems frequently seen in the most challenging and difficult schools. It has only been opened and is unused. Everything in the images is included. Please note that it is made of silicone rubber, so it tends to attract dust.