The fourth dimension

NOMENCLATURE AND ANALOGIES 141

layers on the right. Here, as in the case of the plane, the initial colours repeat themselves at the end of the series.

Proceeding now to increase the number of the cubes we obtain fig. 84, in which the initial letters of the colours are given instead of their full names.

Here we see that there are four null cubes as before, but the series which spring from the initial corner will tend to become lines of cubes, as also the sets of cubes parallel to them, starting from other corners. Thus, from the initial null springs a line of red cubes, a line of white cubes, and a line of yellow cubes.

If the number of the cubes is largely increased, and the size of the whole cube is diminished, we get a cube with null points, and the edges coloured with these three colours.

The light yellow cubes increase in two ways, forming ultimately a sheet of cubes, and the same is true of the orange and pink sets. Hence, ultimately the cube

Fig. 84,