Does the world exist as it appears?
Does this page exist as it appears?
Try and Find the Black Dot!
Do you see a couple or a skull?
Impossible Triangle
Duck (left) or Rabbit (right)?
Are these two verticle line segments the same lengths?
Yes, they are.
Impossible Trident
Impossible Crate
Did you catch the error? Most people don't at first!
Are these lines parallel.
Yes, they are!
The Famous "Face on Mars"
Photo taken by Viking 1 in 1976.
Is it really a face or just an illusion?
Here's the most recent picture that has been
taken of the same rock formation. Doesn't really
look like a face anymore, does it?