It's easy enough to do this: each border vector will have some small ''x'' component, some small ''y'' component, and some small ''z'' component. By choosing our surface elements <math>S_k \ </math> to be in line with the curves of constant ''u'' and curves of constant ''v'' on the surface, these small components will then be | It's easy enough to do this: each border vector will have some small ''x'' component, some small ''y'' component, and some small ''z'' component. By choosing our surface elements <math>S_k \ </math> to be in line with the curves of constant ''u'' and curves of constant ''v'' on the surface, these small components will then be |