The window "Domain" displays a domain, a point (u0, v0) in the domain, a subset of the domain colored red, yellow, cyan, and blue, and a point on the boundary of this subset.

The window "Surface" shows the surface X(u, v), the image of (u0, v0) and the colored subset of the domain on this surface (with each point in the domain mapped to a point of the same color), and the normal vector to X(u, v) at X(u0, v0).

The window "Area Element" shows the graph of the integrand √(g11(u,v)g22(u,v) – g12(u,v)2), which, when integrated, gives the area of X(u,v).

It is possible to drag the two points shown in the "Domain" window to change (u0, v0) and the colored subset of the domain, and it is possible to change X(u, v) in the control window.