In the article, it covers a lot more than three key points. The six key points are similarity, continuation, closure, proximity, figure/ground and symmetry/order.
Similarity- The design has a constant characteristic that is carried out throughout the design.
Continuation- Wherever the eye is led through a line, curve or path.
Closure- Design is seen to be completely closed in, but may not be the case.
Proximity- Element is seen as a whole or separate pieces.
Figure/Ground- Use of light and shadows to create an image.
Symmetry/Order- Image is balanced and not disarrayed.
All of these are shown throughout the article. A message and idea is created with the design having a similar feel. Wherever the eye follows, is the start and the flow of the idea. Closure lacks with examples, the idea is explained but is not really shown with just the World Wildlife Fund logo. How the design is setup and looks, what goes together and what is separate is proximity. Black and white, shadows and space used to create an illusion is the figure/ground of the design. Most important is the symmetry of the design and the order, what comes first, what goes where all incorporated into one idea to show the whole point.
The author supports their points, some evidence/examples could be better shown and explained. Looking at the How Design article in comparison to this article, they show clearly better examples and go into describing the principles better. For example, closure- objects that are well known are still recognizable with still missing some pieces. The nail has been hit in the "Gestalt Principles" article but lacks in a few areas, some image examples lack what is described. Other than that it is well put together and gets the idea across.
