The lengths of the links comply with the conditions: A͞B=E͞C, B͞C=0.32A͞B, A͞E=0.46A͞B, B͞M=M͞C, M͞D=F͞D=D͞L=0.25A͞B, A͞F=1.14A͞B and E͞F=0.85A͞B. Link 1 turns about fixed axis A and is connected by turning pair B to link 2. Link 2 is connected by turning pairs M and C to links 4 and 3. Link 3 turns about fixed axis E. Link 4 is connected by turning pair D to link 5 which turns about fixed axis F. When link 1 turns about axis A, point L of link 4 describes a path of which a certain portion approximates a straight line.
$691$LW,GI$