Similarly, the elegant math gallery helps visitors get a grip on
the basics of visual perception and mechanics. Its 3-D models
lend solidity to abstract topics like projective geometry. Laid
on their sides, two cones painted with long, irregular stripes
puzzle visitors who approach them from the side; step to the
pointy end and view them straight on, and the stripes resolve
themselves into images-a face and the word THINK. The cone
display's idea is echoed in the new Seeing Is Deceiving exhibit
upstairs, which explores how the eye and the brain collaborate
to wring meaning from the huge, messy scribble of color and form
called the world. The exhibit focuses on illusions. Grids trick
the eye into seeing colors that aren't really there; a whirling
vortex makes the viewer's visual field writhe long after the
disk has stopped spinning. The visual perception exhibits, in
turn, shed light on displays in Seeing the Unseen, down the
hall. Camouflage, for example, works best when an animal keeps
still-as museum-goers