Proximity: objects that are close together tend to group themselves together
Similarity: similar objects that are close also tend to form a group
Continuance: it is the idea that the eyes continues at a distance until something significant disrupts the flow
Closure: when an object or space is not completely enclosed, the enough shape indicated, one would tend to perceive it whole without the missing space.
Figure ground: how form (ground) relates to the format (ground)