Linkage for Linear Motions

Grey, blue and pink runways are fixed.
Yellow conrods have the same length.
Angle between grey and blue runways can be adjusted.
Angle of grey/blue runway with pink runway are equal.
Input: green slider.
Output: violet slider.
Distances between green and violet sliders to point O are always equal.
Speeds of the input and output are equal.
The mechanism has an unstable position when the yellow conrods are perpendicular to grey and blue runways. At this position when green slider moves towards point O, violet slider may move away from point O.