This is preceded by a discussion of the definition of a 4 dimensional cube as shown in the diagrams:
The cube in each dimension is constructed by drawing 2 cubes of the previous dimension (blue and red) and connecting corresponding vertices (magenta).
There was also a discussion of viewing in perspective and using color to visualize the 4th dimension.
The movie was followed by an introduction to rotations in special relativity and the definition of a 4 dimensional pyramid as shown in the diagrams:
The pyramid in each dimension is constructed by drawing a pyramid of the previous dimension (blue), adding a point (red) and connecting the new point to each of the old vertices (magenta).