line 91 is drawn between pivot 81 and 85 line 92 is drawn between pivot 84 and 83 the intersection of lines 91 and 92 is at the center point of pivot 90 0068 fig1 shows linkage 70 drawn in a different position line 93 passes through pivots 81 and 85 line 94 passes through pivots 84 and 83 the intersection of lines 93 and 94 is again at the center point of pivot 90 which lies opposite the two four pivot links 72 and 74 the angle formed between lines 93 and 94 is identical to that formed between line 91 and 92 in fig1 in general given an equal sided parallel four bar linkage where two of the links each have two pivots and two other links each have four pivots which lie on the vertices of two mirrored isosceles triangles and of those four pivots two lie on the mirror line and are attached to neighboring links and two are side pivots which remain unattached two lines may be drawn each connecting between the side pivots of neighboring links which two lines will form an angle that is constant and unchanging for any relative position of the linkage and will always intersect that pivot which lies opposite the two four pivot links 0070 fig1 shows a linkage 100 consisting of.