kofeffect got it right!
16: Are the circles rotating?
No. The image appears to be in constant motion, but in fact it is completely stationary. (86% answered correctly)
I17: How many triangles are there?
There are no triangles. Most people see 2 triangles. In fact, there are only 3 Pacman shapes and 3 V shapes. (48% answered correctly)
I18: Straight or bent???
Perfectly straight. Those of you with keen eye for details will notice the light background shares the same effect. (84% answered correctly)
