The following five 3D graphics are all plots of the prepayments of a Pass Through security (Mortgage Backed Security) with a principal of USD 100, a coupon rate of 8 percent nominally, monthly settlements, 40 settlements to maturity and a service fee of 0.25 percent. The PSA percentage is varied between 0 and 1000. The time to maturity in the 3D graphics are measured in months, and the prepayment rate is measured in percent. The five plots are all the same, but viewed from different angles (ViewPoint -> {x, y, z}).

Note how the prepayments become greater the greater the PSA percentage. Note also how important the viewpoint of a 3D graphic is.

1. ViewPoint -> {0, -4, 1}
   
2. ViewPoint -> {0, -4, 0}
   
3. ViewPoint -> {-2, -2, 1}
   
4. ViewPoint -> {-4, 0, 1}
   
5. ViewPoint -> {-4, 0, 0}