[pstricks] multido again

[Michael Sharpe]

Zbigniew,

You cannot use PostScript code to specify a radius. The PSTricks  
parser understands PostScript in coordinates and angles, so you can  
use instead

\begin{pspicture}[showgrid=true](-3,-3)(3,3)
		\psarc[linewidth=1.2pt,arrows=->](0,0){2}{0}{180}
		\multido{\rt=10+10}{4}{%
			\psellipticarc(!0 \rt\space 2 mul cos neg)%
				(!\rt\space cos 2 mul dup){!\rt\space}{!180 \rt\space sub}
		}
\end{pspicture}

Michael

On Dec 4, 2008, at 1:15 PM, Zbigniew Nitecki wrote:

> 		\psarc[linewidth=1.2pt,arrows=->](0,0){2}{0}{180}
> 		\multido{\rt=10+10}{4}{%
> 			\psarc(!0 \rt\space 2 mul cos neg)%
> 				{!\rt\space cos 2 mul}{\rt}{!180 \rt\space sub}
> 		}
>