\documentclass{article}\begin{document}\directlua{ function p(h,w,t) for i=1,h do tex.print("\\centerline{"..("*"):rep(2*i-1).."}")end for i=1,t do tex.print("\\centerline{"..("*"):rep(w).."}")end tex.print("\\centerline{Merry Xmas}") end}\def\P#1,#2,#3{\directlua{p(#1,#2,#3)}}\P30,5,7\end{document}
<code>\documentclass{article}\begin{document}\directlua{
function p(h,w,t)
for i=1,h do tex.print("\\centerline{"..("*"):rep(2*i-1).."}")end
for i=1,t do tex.print("\\centerline{"..("*"):rep(w).."}")end
tex.print("\\centerline{Merry Xmas}")
end}\def\P#1,#2,#3{\directlua{p(#1,#2,#3)}}\P30,5,7\end{document}</code>

