The lengths of the links comply with the conditions: 0͞B=C͞D=a. Slider 1 turns about fixed axis 0. Link 3 is connected by a sliding pair to slider 1. Cross-piece Cd of link 3 is connected by a sliding pair to slider 2 which turns about fixed axis B. When slider 1 turns about axis 0, point D of link 3 describes cardioid q-q. The same cardioid is also described by another point of link 3, located at the distance a to the left of point C. The equation of the cardioid is ρD=0͞D=a(1+cos(ϕ)) where ϕ is the polar angle between vector ρD and polar axis 0x.
$1145$LG,Ge$