Depth Cues

Here I am just posting some examples of the cues that help us to recognize depth in a planar image:
This image has contradicting cues. It has the depth cue from the squares pattern receding to a horizon point, and uses height of the subjects to indicate depth. However, the size of the figures contradicts how we would expect things to appear as they are further back from us.
















In the image below which is in front? The circle or the square shape? The lack of clarity, or blurriness is an indicator to us that an image is further back. This technique is very popular in animation as a Gaussian blur can increase the depth of a flat image.










We perceive depths in objects relations to each other. Generally we perceive things as being 'in front of' or 'in back of', but in reality, this relationship only exists in our minds and not in the picture itself.















Also utilizing the height principle and use of shadows, in which we have real world experiencing in perceiving, how do you label these objects' relationships to each other?