The window "Domain" displays a domain and a point
(u_{0},
v_{0}) in the domain.

The window "Surface: X(u, v)" shows the sphere X(u, v) = (cos(u)cos(v), sin(u)cos(v), sin(v))
and the point X(u_{0}, v_{0}).

The window "Coefficients of 2nd
Fundamental Form" window graphs L_{11}(u,v), L_{12}(u,v)
= L_{21}(u,v), and L_{22}(u,v) in red, green, and cyan,
respectively.

It is possible to click and drag the
point (u_{0}, v_{0}) in the
domain.