Optical Illusion

Look closely at tile A and B. They seem to be different shades of gray. They are the same exact shade. Don't believe it? Try opening up the image in Paint or another image editor and put the 2 tiles side by side

He looks like moving in space

That Spider too is moving

A set of circles or a spiral?

This is something to this day I can not figure out. The more I look at it and analyze the more confused I get. If you know the answer then it is fine else , Will the answer