\usepackage {pstcol,pst-node,pst-tree} \psset{framearc=.2,levelsep=4cm, armB=1cm,angleB=-180} \renewcommand{\psedge}{\ncangle} \newcommand{\TreeBox}[1]{\Tr{\psframebox{#1}}} \pstree[treemode=R]{\TreeBox{Monitor}} {\psset{offsetA=4pt} \TreeBox{Attitude Generator} \naput[npos=2.5]{{\small init}} \nbput[npos=2.5]{{\small stop}} \psset{offsetA=-4pt} \TreeBox{Normal Generator} }