Our mind is the final arbiter of truth...

 The red squares are the same color in the upper part
and in the lower part of the "X"

 

There are no gray spots at the corners of the squares.

 

The rows of black and white squares are all parallel.

 

Impossible Triangle.

 

Do you see a musician or a girl's face?

Parallel lines at sunrise.

 

The center circles are both the same size.

 

The Vertical lines are both the same length.

 

Three-prong fork.

 

There are only white circles at the intersections

 

Wavy Squares? No!
The background of concentric circles makes the squares appear distorted.

 

Rotating Wheels
The circles appear to rotate when you move your head closer and
further away from the screen while looking at the dot in the center. 

 

Warped Square?
There are no curved lines in this figure. 

 

 Keep staring at the black dot...
After a while the gray haze around it will appear to shrink.

Instructions from Hell:

It's a spiral, right?

Never make a decision based only on your observations ...