Final answer:
Figure-ground reversal is not a technique to imply depth on a 2D picture plane. Diminishing size, vertical placement, and overlap are commonly used techniques to create the illusion of depth.
Step-by-step explanation:
The technique that is not used to imply depth on a 2D picture plane is figure-ground reversal.
In art, figure-ground reversal refers to the alternating positive and negative spaces created by the relationship between the object (figure) and its background (ground). It does not create a sense of depth, but rather plays with perception and spatial relationships.
On the other hand, techniques like diminishing size, vertical placement, and overlap are commonly used to create the illusion of depth in a 2D picture plane. For example, by making objects smaller as they recede into the distance, or by overlapping objects, artists can suggest depth and a sense of spatiality in a flat image.