Toysmith Euler's Disk Description Fascinating desktop illusions! Spin the holographic disk on the mirror. Does it speed up? Listen to its rhythmic sounds. Why does the humming get louder as the speed of the disk increases? This patented 3" Diameter chrome-plated steel disk creates a hypnotic display of light and sound as it rotates. Includes Euler's disk, 9" Concave mirror base and nine pieces of magnetized holographic foil. Complete with instructions and the scientific answers! From the Manufacturer Give the Euler's Disk! This patented 3" diameter chrome-plated steel disk creates a hypnotic display of light and sound as it rotates. Includes Euler's Disk, 9" concave mirror base and nine pieces of magnetized holographic foil. Features: Spin science into art Disk will spin faster and louder the longer it goes Creates a hypnotic display of light and sound as it rotates Just give this fidget toy a spin and gravity does the rest Use this office toy to reduce anxiety and increase focus A giftable mind game to promote an interest in science Patented 3" diameter chrome-plated steel disk Includes Disk, 9" concave mirror base and 9 pieces of holographic foil Patented 3" diameter chrome-plated steel disk Creates a hypnotic display of light and sound as it rotates Includes Disk, 9" concave mirror base and 9 pieces of holographic foil Foil is magnetized Product Details: Brand: Toysmith Theme: physics Age Range (Description): Adult Item Dimensions LxWxH: 10 x 9.5 x 1.5 inches Item Weight: 1.61 Pounds Product Dimensions: 10 x 9.5 x 1.5 inches Item Weight: 1.61 pounds Country of Origin: Taiwan Item model number: 791709 Manufacturer recommended age: 8 years and up Is Discontinued By Manufacturer: No Release date: June 1, 2017 Manufacturer: Toysmith