Benham's top

For people who check facts

Also called Benham's disk, is named after the English toymaker Charles Benham, who , in 1895, sold a top painted with the pattern shown. See picture.

When the disk is spun, arcs of pale color are visible at different places on the disk. These are called called Fechner colors. Not everyone sees the same colors.

The phenomenon is not entirely understood. One possible reason people see colors may be that the color receptors in the human eye respond at different rates to red, green, and blue.

External links

http://faculty.washington.edu/chudler/benham.html