The concept of figure/ground, or positive/negative shape, is taught to all design students. This is a perceptual organization that assigns edges to areas. It allows us to read imagery and discern shape, hence decide what we think the picture shows. Perceiving the subject (figure) from its context (ground) is made possible by dark/light contrast. The most famous example of this is the Rubin faces/vase drawing. Depending on whether the white or black color is seen as the figure or the ground, the brain will interpret the picture as two different images.
Here’s a fun link that shows figure/ground relationships in famous corporate logos. Like this:
The second and third “t’s” are sharing a chip over a bowl of salsa!