autocrop
-6 6 setxrange
-6 6 setyrange
25 setxunit
10 10 10 SetCamPos
0 0 0 SetCamView
qplanxy
2 setlinejoin 
10 10 10 setlightsrc

/f {
2 dict begin
   /v exch def
   /u exch def
#rpn# 5 * Cos (u)
#rpn# 2 * Sin (u)
   v
end
} def

.2 setlinewidth
.4 setgray
   0 pi 2 mul 1 sub
   -1 5
   [.3 .3]
{f} newsurfaceparametree
dup [.3 .5] solidputinouthuecolors
drawsolid**