Top:PhiTOP

The PhiTOP spinning toy, "a prolate ellipsoid with a ratio of 1:1.618" (the Golden Mean), demonstrates the dynamics of an egg-shaped spinning top: if spun on its horizontal axis, it will "flip" to spin on its vertical axis. The toy, designed by a Boston University professor of physics and launched with a Kickstarter campaign, includes a pamphlet that explains Lenz's Law of electrodynamics, Lissajous figures as the top begins to slow down, and the illusion of the gelatinous ellipsoid effect of the top losing its solid egg shape as its spinning slows down.