The Necker Cube, an optical illusion. See how the Cube "mysteriously" changes perspective while you watch. Applet Author Mark Newbold has invented a unique portrayal of the Necker Cube here. Return Home Quick Links Mind Bluff Links Optical Illusions A cross-section of different themes designed to fool the mind. Four Squares Problem Reposition 2 sticks so that you have four squares of equal size and no sticks left over. Marble-Weighing Problem 12 marbles all weigh the same except one. Perform a maximum of three weighings to find the odd man out. Mensa-level test. Fast Questions Four simple questions designed to stump you. Speed Panel Words are flashed at subliminal speed: Which ones do you detect, and why? Hand Shadow Illusions Hand Shadows cast upon a wall. Experience these cool human art forms! Speed Reading Tests Compute reading speed and comprehension scores in these timed and untimed reading tests. Reaction Time Test Hit the dots and discover your mental reaction time. 30-second test. Create a Fake Phantom Limb Experience the illusion of a tactile limb attached to your body. When Words Collide Words can be illusions -- in the guise of puns. Enter a landscape of double meanings. More Stuff MUCH MORE content on the main page!