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**