A number of LOD points in the Perfect Club are extremely difficult to optimize; perhaps even impossible. The most notable examples occur in SPICE, and are illustrated in figures 17, 18 and 19.
Figure 17: A difficult LOD to optimize from SPICE, and one of the most
frequent (click on image to view at full scale)
Figure 18: A difficult LOD to optimize from SPICE, and one of the
most frequeny (click on image to view at full scale)
Figure 19: Another difficult LOD to optimize from SPICE (click on image to view at full scale)