Bet they can't build one that moves inwards and outwards.,(reply>), @Alphonso ButlakIV That's literally how a tri-dimensional space works. "Up" and "down" are also "side to side, but the other way", as you put it.<br>Up, down, left, right, in, out.,(reply>), @Patrick Tho that would still just be side to side, but the other way.,(reply>), You just got to change the coordinate system or change the rotational axis.