Lower face Light-grey Rose Sea-blue Upper White Deep-brown Deep-green Left-hand Light-red Yellow-ochre Deep-crimson Right-hand Deep-brown Blue-green Dark-grey Near Ochre Yellow-green Dun Far Deep-green Dark-grey Light-yellow Lines:-- On ground, going round the square from left to right:-- 4 6 8 1. Brown-green Smoke Dark-purple 2. Dark-green Crimson Magenta 3. Pale-yellow Magenta Green-grey 4. Dark Dull-green Light-green Vertical, going round the sides from left to right:-- 1. Rich-red Dark-pink Indigo 2. Green-blue French-grey Pale-pink 3. Sea-green Dark-slate Dark-slate 4. Emerald Pale-pink Green Round upper face in same order:-- 1. Reddish Green-blue Pale-yellow 2. Bright-blue Bright-blue Sea-green 3. Leaden Sea-green Leaden 4. Deep-yellow Dark-green Emerald Points:-- On lower face, going from left to right:-- 1. Quaker-green Turquoise Blue-tint 2. Peacock-blue Fawn Earthen 3. Orange-vermilion Terra-cotta Terra-cotta 4. Purple Earthen Buff On upper face:-- 1. Light-blue Peacock-blue Purple 2. Dull-purple Dull-purple Orange-vermilion 3. Deep-blue Deep-blue Deep-blue 4. Red Orange-vermilion Red If any one of these cubes be taken at random, it is easy enough to find out to what part of the Tessaract it belongs. In all of them, except 2, there will be one face, which is a copy of a face on 1; this face is, in fact, identical with the face on 1 which it resembles. And the model shows what lies in the unknown direction from that face. This unknown direction is turned into our space, so that we can see and touch the result of moving a square in it. And we have sacrificed one of the three original directions in order to do this. It will be found that the line, which in 1 goes in the 4th direction, in the other models always runs in a negative direction.