The blue plate is driving.
The green plate moves two times faster than the blue one.
The violet plate moves two times faster than the green one or four times faster than the blue one.
The sprockets have the same tooth number.
The lower pink link of the front chains is fixed to the base.
The upper pink link of the front chains is fixed to the green plate.
The lower red link of the back chains is fixed to the blue plate.
The upper red link of the back chains is fixed to the violet plate.
The blue plate carries the front chain drive.
The green plate carries the back chain drive.
The mechanism can be used for telescopic sliding gate of three panels.