Input: pink cranks.
Center of the pin on a green satellite pinion traces an equilateral triangle of rounded vertices.
Yellow vertical bar translates following the said triangle thanks to a parallelogram mechanism (two green cranks and yellow conrod).
Internal gear: tooth number: 30; module: 3 mm
Pinion: tooth number: 20; module: 3 mm
Length of the pinion crank: 55 mm
Length of the pink crank: 15 mm
To draw a complete equilateral triangle the pink crank rotates 2 revolutions.
Time for tracing straight portion is nearly 1/3 of working period.