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

The window "Area
Element" shows the graph of the integrand √(g_{11}(u,v)g_{22}(u,v)
– g_{12}(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 (u_{0},
v_{0})
and the colored subset of the domain, and it is possible to change X(u,
v) in the control window.