-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 solideqplansepare
dup (orange) solidputcolors
dup videsolid
/planA1 exch def

dup (orange) solidputcolors
dup videsolid
/planA2 exch def

eq2 20 eq2plan
dup [-3 3 -3 3] planputrange
dup [.5 dup] planputngrid
newplan
%eq1 solidplansection
dup (.4 setfillopacity cyan) solidputcolors
dup videsolid
/planB exch def

planA1 
drawsolid**
planB
drawsolid**
planA2 
drawsolid**

20 setfontsize
setTimes
(En séparant les plans)
xmin ymin xmax ymin milieu uctext