The lengths of the links comply with the conditions: C͞D=D͞B and E͞D=F͞B=D͞F=F͞A=A͞E=C͞E. When point A traces around any outline lying in the plane of the drawing, point B of link 2, lying on straight line CAq describes a similar outline with a similarity factor k equal to C͞D/C͞E= 2.
$831$LW,P$