We can consider the cube to be produced in the following way. A null point moves in a direction to which we attach the colour indication yellow; it generates a yellow line and ends in a null point. The yellow line thus generated moves in a direction to which we give the colour indication red. This lies up in the figure. The yellow line traces out a yellow, red, or orange square, and each of its null points trace out a red line, and ends in a null point. This orange square moves in a direction to which we attribute the colour indication white, in this case the direction is the right. The square traces out a cube coloured orange, red, or ochre, the red lines trace out red to white or pink squares, and the yellow lines trace out light yellow squares, each line ending in a line of its own colour. While the points each trace out a null + white, or white line to end in a null point. Now returning to the first block of eight cubes we can name each point, line, and square in them by reference to the colour scheme, which they determine by their relation to each other. Thus, in fig. 86, the null cube touches the red cube by a light yellow square; it touches the yellow cube by a pink square, and touches the white cube by an orange square. There are three axes to which the colours red, yellow, and white are assigned, the faces of each cube are designated by taking these colours in pairs. Taking all the colours together we get a colour name for the solidity of a cube. [Illustration: Fig. 86.] Let us now ask ourselves how the cube could be presented to the plane being. Without going into the question of how he could have a real experience of it, let us see how, if we could turn it about and show it to him, he, under his limitations, could get information about it. If the cube were placed with its red and yellow axes against a plane, that is resting against it by its orange face, the plane being would observe a square surrounded by red and yellow lines, and having null points. See the dotted square, fig. 87. [Illustration: Fig. 87.] We could turn the cube about the red line so that a different face comes into juxtaposition with the plane. Suppose the cube turned about the red line. As it is turning from its first position all of it except the red line leaves the plane—goes absolutely out of the range of the plane being’s apprehension. But when the yellow line points straight out from the plane then the pink face comes into contact with it. Thus the same red line remaining as he saw it at first, now towards him comes a face surrounded by white and red lines.