Gear Cube Extreme

Invented by Oskar van Deventer, purchased from Mefferts, 2011.
(plastic, 2.3 inches)

A harder to solve version of the Gear Cube where the edge pieces along the middle layer are not geared; shipped with stickers to go in the black U's below the gears to make a more difficult puzzle that Mefferts calls the "Gear Cube Extreme". Six turns bring the puzzle back to its shape; below are some example moves. Jaap's Page presents a solution.

Further Reading
Mefferts Page, from:
Jaap's Page, from: