Using Kaplan-Meier curves, a graph of the log(-log(survival)) vs log of survival time should show
parallel curves. An example of a Cox proportional hazards fit of drug data is shown in Figure 4.
In fact, planar curves together with their
parallel curves are Bertrand mates.
Of course Currin's works are not prints, but he has got the myriad
parallel curves of the chiaroscuro print down pat.
Bold painted lines mark all areas of the painting, from the
parallel curves of the woman's hair to the hat with its flower decoration.
The center curve is the predicted mean value of the estimator; the
parallel curves indicate the predicted data spread within plus and minus two standard deviations.