apparatus comprising a three dimensional cubic space displayed on a display screen, the cubic space having a series of horizontal planes extending through the side walls and through the rear wall and the front wall, a first series of vertical planes extending through the rear wall and front walls and through the top and bottom walls, and a second series of vertical planes extending through the bottom and top walls and the side walls of the cubic space and wherein one of the two images is moved in a single direction in one of either of the series of vertical planes using a fourth pair of keys and/or moved in a single direction in one of series of the horizontal planes using a fifth pair of keys.
Still anotherdisplay screen having a first image of a three dimensional object and a second image of a three dimensional object randomly placed therewithin wherein the cubic space has a vertical axis, a first horizontal axis and a second horizontal axis, the vertical axis and the first and second horizontal axes crossing as the center of the cubic space and wherein the cubic space may be rotated about the first horizontal axis and/or rotated about the vertical axis wherein a subject to be tested faces the space from a position relative to front face and moves the images into convergence in the center of the cubic space by observing the first and second images through an open front wall of the cubic space wherein the front face aperture is