\documentclass[pstricks,border=12pt]{standalone}

\def\A#1{%
\begin{pspicture}[showgrid,dimen=m](7,5)
\rput(3.5,4.5){psarcn with liftpen=#1}
\pscustom
{
	\moveto(1,1)
	\psarcn[liftpen=#1](4,2){2}{180}{0}
	%\closepath
}
\end{pspicture}}

\def\B#1{%
\begin{pspicture}[showgrid,dimen=m](7,5)
\rput(3.5,4.5){psellipticarcn with liftpen=#1}
\pscustom
{
	\moveto(1,1)
	\psellipticarcn[liftpen=#1](4,2)(2,2){180}{0}
	%\closepath
}
\end{pspicture}}


\begin{document}
\foreach \i in {0,1,2}{\A{\i}}
\foreach \i in {0,1,2}{\B{\i}}