Source PostScript (mulc.pps)

%% multiplication de 2 complexes
%% syntaxe : a b a' b' mulc --> x y
/mulc {
4 dict begin
   /b' exch def
   /a' exch def
   /b exch def
   /a exch def
   a a' mul b b' mul sub
   a b' mul a' b mul add
end
} def