Wonderful Perspective Machine- The Perspective Machine is a combination of two thoughts, OLD and NEW. The viewer is as old as the ancient Greeks - hold at arms length, scan around and pick your composition. The grid on the blue plastic has 3 lines vertically and 3 lines horizontally - you mark lightly the same lines on your paper or canvas, which has approximately the same proportions. Now comes its major function. There is a magnetic inner frame with spring steel cross bars that go in any direction you place them - and stay. So all you have to do is line up the bars with your various angles, note where they cross the squares on the viewer, then mark the same on your squared-off canvas or paper - how can you miss?