' - - File: VII_FieldB1.txt

' Plot a "simple surface" directed field.

F{x,y} = x + y
G{x,y} = x - y
H{x,y} = 16 - x^2 -y^2

PlotDirField[F, G, H, {-4,4,25}{-4,4,25}]

' After the graph is displayed:
'     use the cursor keys to get a better angle of view;
'     Color the axes to see it relative to the image.


