%% syntaxe : x y z a11 a21 a31 a12 a22 a32 a13 a23 a33
%%    transformpoint3d -> X Y Z
/transformpoint3d {
12 dict begin
   /a33 exch def
   /a23 exch def
   /a13 exch def
   /a32 exch def
   /a22 exch def
   /a12 exch def
   /a31 exch def
   /a21 exch def
   /a11 exch def
   /z   exch def
   /y   exch def
   /x   exch def
   a11 x mul a12 y mul add a13 z mul add
   a21 x mul a22 y mul add a23 z mul add
   a31 x mul a32 y mul add a33 z mul add
end
} def