Identical pulleys 2 and 6 rotate about axes A and B of the straight- edge. Rigidly attached to pulleys 2 and 6 are identical pulleys 3 and 7. Flexible link (cable) 4, shown by a dash line, runs over pulleys 3 and 6, and is attached to the base (drawing board) at points C and E. Flexible link (cable) 5, runs over pulleys 2 and 7, and is attached to the base (drawing board) at points D and F. Straightedge 1, on which the axles of pulleys 2, 3, 6 and 7 are mounted, travels along axis y-y with translational motion, so that its edges remain parallel to axis x-x.
$3532$CFL,ML$