The lengths of the links comply with the condition: A͞B:A͞C=B͞Q:C͞P. Link 2 turns about fixed axis A which is the centre of inversion transformation. Links 3 and 5 are connected by turning pairs B and C to link 2, and by turning pairs Q and P to sliders 4 and 6 which move along axis Aa of link 1. Link 1 turns about axis A. When point P or Q travels along any arbitrary curve, the other point describes a curve which is the inversion of the first curve. Hence, the mechanism accomplishes inversion transformations of the form A͞PxA͞Q=A͞BxA͞C=const.
$1366$LG,GI$