The ezsurf(f) calling sequence plots the 3-D surface described by the 2 variable expression, f.

xmin and xmax denote the left and right endpoints of the horizontal range.  ymin and ymax denote the vertical endpoints.  When omitted, the default range is -Pi .. Pi.

When three expressions are given as the first arguments in the ezsurf calling sequence, an implicitplot3d of f(s,t), g(s,t) and h(s,t) is generated.

The range limits correspond to the order of alphabetically sorted indeterminates.

When the keyword option 'circ' is given, the plot is a disk.