Input: pink slider of Vp velocity carrying orange gear.
Output: yellow slider of Vy velocity. Yellow rack is fixed to the yellow slider.
Green rack is fixed to green slider of Vg velocity that carries blue gear.
Brown and grey racks are stationary.
The gears are of the same tooth number.
The orange gear is in mesh with the brown and green racks.
The blue gear is in mesh with the grey and yellow racks.
Vy = 4Vp
Vg = 2Vp