Most people would be like, "A 3D square is called a cube". But no, a cube is this project: https://scratch.mit.edu/projects/507397804/. A 3D square is like a square piece of paper in real life. It has no third dimension, but if you look at it from different angles, that's what makes it appear 3D (the different angles). Basically, a 3D square is a 2D square in a 3D world.
