The lengths of the links comply with the condition: A͞B=B͞C=C͞D=D͞A, i.e. figure ABCD is a rhombus linkage. Links 1 and 4 are connected by turning pairs A to slider 2 and by turning pairs D and B to links 6 and 5 which, in turn are connected by turning pairs C to slider 3. Sliders 2 and 3 move along fixed guides p-p. When point B is moved along a curve with the equation F(x,y)=0, then point D describes curve P(ξ,η)=0. Coordinates x, y, ξ and η are related by the conditions: x=ξ and y=η. Hence the mechanism can trace a mirror image of a curve with respect to axis 0x, or it can be used to trace two portions of the same curve which are symmetrical with respect to some straight line.
$1609$SC,Ge$