1. The gestalt law of parallel movement The book by Lauesen, User Interface Design, illustrates many of the gestalt laws, but cannot illustrate the law of parallel movement: Things that move in parallel, are perceived as belonging together. This file gives a striking illustration of the law. Print the first four slides on transparencies. On an overhead, put Cross and CrossBackground on top of each other. It just looks like rain dots. Move the Cross transparency. The cross gestalt becomes visible, but as soon as movement stops, the gestalt disappears. Do the same with Elephant and ElephantBackground. Notice that now the gestalt is visible for a few seconds after movement stops. The vision-center models in section 3.4 can explain this difference. How? The file also has two slides with figure on top of the background. Drag the handle (the triangle) to make the figure move (or use the arrow keys). It cannot give the same smooth movement and gestalt effect as on the overhead. (At least not with my computer setup.) The effect is best for the elephant. © Lauesen, 2004

2. Cross © Lauesen, 2004

3. CrossBackground © Lauesen, 2004

4. Elephant © Lauesen, 2004

5. ElephantBackground © Lauesen, 2004

6. Cross & Background © Lauesen, 2004

7. Elephant & Background © Lauesen, 2004