A 3D solid object in the 3rd Spatial dimension casts a 2D flat shadow. (It remembers the dimension below) __________________________________________________________________________ A 3D Cube in the 4th Spatial dimension turns into a Tesseract. This is a Cube with six Square based Cones meeting in the middle, thus remembering the Cube's 2D Surface Areas. A 3D Sphere in the 4th Spatial dimension turns into a Hypersphere. This is a Sphere with Cones projecting from it, each the length of the Radius, thus remembering the 2D Diagonal Radii. A 2D Rectangle in the 4th Spatial dimension turns into a Mobius strip. This is a continuous curve, thus remembering the Rectangle's 1D Perimeter. A 1D Line in the 4th Spatial dimension turns into a Complex Plane. This attaches an Imaginary Number to each Point of the Line, thus remembering the Line's 0D Points. They said it would take someone with great imagination to understand the 4th Spatial Dimension, and I've done just that. Enjoy.