-5 4 setyrange
-6 5 setxrange

-5 7 2 SetCamPos
0 0 0 SetCamView
50 setxunit
GetCamPos setlightsrc
2 setlightintensity
2 setlinejoin

/eq1 [1 0 -2 0] def   %% equation plan 1
/eq2 [0 1 0 0] def    %% equation plan 2

eq1 30 eq2plan
dup [-3 3 -3 3] planputrange
dup [.5 dup] planputngrid
newplan
eq2 solidplansection
dup (orange) solidputcolors
dup videsolid
/planA exch def

eq2 eq2plan
dup [-3 3 -3 3] planputrange
dup [.5 dup] planputngrid
newplan
eq1 solidplansection
dup (cyan) solidputcolors
dup videsolid
/planB exch def

planA planB
solidfuz
drawsolid**