Optical Illusions

Shades of Grey The colors look the same, but are they the same?	Broken Line Illusion Can you mend the broken line?
Which Line is the Longest? It looks obvious, but don't be so sure!	Line Lengths Can you believe that the lines are the same length?
Impossible Triangle Check out this cool 3-D shape. There's something strange going on here...	Curved Lines? They sure do look curved, but are they?
Which is Bigger? Can you tell which circle is the biggest?	Never-Ending Staircase This staircase will never let you reach the bottom!
Which Circle is Smaller? Can you point out the smallest circle?	Invisible Squares Stare at this image and squares will appear before your eyes!