We will see what change could be introduced into the shapes he builds by the movements, which he does not know in his world. Let us build up this shape with the cubes of the Block: Urna Mala, Moles Mala, Bidens Mala, Tibicen Mala. To the plane-being this shape would be the slabs, Urna Moena, Moles Moena, Bidens Moena, Tibicen Moena (Fig. 15). Now let the Block be turned round the Z axis, so that it goes past the position, in which the Alvus sides enter the vertical plane. Let it move until, passing through the plane, the same Moena sides come in again. The mass of the Block will now have cut through the plane and be on the near side of it towards us; but the Moena faces only will be on the plane-being’s side of it. The diagram (Fig. 16) shows what he will see, and it will seem to him similar to the first shape (Fig. 15) in every respect except its disposition with regard to the Z axis. It lies in the direction -X, opposite to that of the first figure. However much he turn these two figures about in the plane, he cannot make one occupy the place of the other, part for part. Hence it appears that, if we turn the plane-being’s figure about a line, it undergoes an operation which is to him quite mysterious. He cannot by any turn in his plane produce the change in the figure produced by us. A little observation will show that a plane-being can only turn round a point. Turning round a line is a process unknown to him. Therefore one of the elements in a plane-being’s knowledge of a space higher than his own, will be the conception of a kind of turning which will change his solid bodies into their own images. CHAPTER VI. THE MEANS BY WHICH A PLANE-BEING WOULD ACQUIRE A CONCEPTION OF OUR FIGURES. Take the Block of twenty-seven Mala cubes, and build up the following shape (Fig. 18):-- Urna Mala, Moles Mala, Plebs Mala, Pallor Mala, Mora Mala. If this shape, passed through the vertical plane, the plane-being would perceive:-- (1) The squares Urna Moena and Moles Moena. (2) The three squares Plebs Moena, Pallor Moena, Mora Moena, and then the whole figure would have passed through his plane. If the whole Block were turned round the Z axis till the Alvus sides entered, and the figure built up as it would be in that disposition of the cubes, the plane-being would perceive during its passage through the plane:-- (1) Urna Alvus; (2) Moles Alvus, Plebs Alvus, Pallor Alvus, Mora Alvus, which would all enter on the left side of the Z axis. Again, if the Block were turned round the X axis, the Syce side would enter, and the cubes appear in the following order:-- (1) Urna Syce, Moles Syce, Plebs Syce; (2) Pallor Syce; (3) Mora Syce. [Illustration: Fig. 17.] [Illustration: Fig. 18.] A comparison of these three sets of appearances would give the plane-being a full account of the figure. It is that which can produce these various appearances.