\documentclass[pstricks,border=2pt]{standalone}
%\usepackage{etex}
%\reserveinserts{100}
\usepackage{pstricks}
\SpecialCoor
\psset{showpoints=true,unit=10mm}
\usepackage{multido}
\usepackage{fp}
\def\Atom#1{%
\ifnum#1=1\relax
\pspolygon(0,0)(!.5 dup 3 sqrt mul neg)(1,0)
\else
\def\SubAtom{\expandafter\Atom\expandafter{\the\numexpr#1-1\relax}}%
\rput(0,0){\SubAtom}
\rput{-60}(!2 #1 2 sub exp 0){\SubAtom}
\rput(!2 #1 2 sub exp 0){\SubAtom}
\rput(!2 #1 3 sub exp dup 3 sqrt mul neg){\SubAtom}