Figure 3: Shape functions used for simulations. These two functions are aligned versions of g1(x)=0.2exp{−20(x−0.2)2} and g2(x)=(exp{−0.7x}– exp{−12x}) I(0,1).They are similar, but certainly NOT identical, in shape. Note also g2 is not differentiable at the initial rise, which creates a situation where multiple knots are desirable in that region. The simulations consisted of generating 40 datasets, each with 100 functions, 50 of which are selfmodeling versions of g1 with error and 50 of which are self-modeling versions of g2 with error.