My question is dealing with shadows. I noticed this the other day while standing outside. The shadow that the building cast was on the ground in front of me and was very close to my shadow. I swayed slightly and noticed that both shadows were attracted to one another to the point where they moved, independently of my own movement, and touched. The shadows sppeared "warped"; the straight linear shadow of the building was now slightly bent. Just being curious I thought this would be the best place to ask. What is this called?