Pink workpieces are slapped between two grey disks.
Input 1: green pulley to which green gears are fixed.
Input 2: blue shaft of blue gear.
Blue shaft has two eccentric portions on which two grey gears with slapping disks rotate. The upper grey gear can move axially a little.
The grey gears engage with green lower and upper internal gears.
So blue, grey and green (upper and lower) gears create a planetary drive.
Yellow gears are in mesh with the central blue gear and green middle internal gear.
So blue, yellow and green (middle) gears create a planetary drive without a carrier.
Height of the yellow gears is slightly smaller than the one of the workpieces.
Blue spring forces upper slapping disk toward the lower one.
Yellow gears and workpieces have complicated planar motion which can be set by adjusting input speeds.