' - - File: XII_Contour4a.txt

F{x,y}= -x^3 /3 + x - y^2

r = 12 :  er = 0.2  :  sg = 1

Ux<t> = <t,0,0> : Uy<t> = <0,t,0>  :  Uz<t> = <0,0,t>
Plot[Ux,Uy,Uz,{t,-r,r,100}]

PlotContour[F,{-r,r,-r,r}{6,6}{-20,20,2}{er,sg}]

' Example to use larger er & sg segment size to obtain a quick scan.
' Note how the level range increased with larger step size (4) to spread out
'      the contour mappings. If this plot (or any contour plot) looks interesting, we
'      can lower the er = 0.1 and segment, sg = 0.25 or 0.2, Then take a lunch break.







