Muller Illusions

You will find a number of pictures here that are slightly different when you take a look at them. Where is the beginning, where is the end? Escher kind of illusions are not the only kind you will find here.
Are the lines straight or bend? Whos is larger? How come it looks like the picture is moving? And more.

Click on the link to see the picture:
Night sky curtains
Can you count the black dots?
Autumn Path
Carved in stone
straight lines, or bend?
Who is taller?
flooding away
where do these gray dots come from
moving
Parallel lines?
Skating in the sky
Who is the artist?
Puzzling
Elephant