\input fig4tex.tex

% 1. Definition of characteristic points
\figinit{pt}
\figpt 1:(-10,10)
\def\haxis{100}
\def\vaxis{40}
\def\inclin{45}
\def\startangle{-20}
\def\stopangle{160}
\figptell 11::1 ;\haxis,\vaxis(0,\inclin)
\figptell 12::1 ;\haxis,\vaxis(90,\inclin)
\figptellP 30:$B$:1,11,12(-20)
%
% 2. Creation of the graphical file
\figdrawbegin{}
\figdrawarcell 1 ;\haxis,\vaxis( \startangle,\stopangle , \inclin)
\figdrawend
%
% 3. Writing text on the figure
\figvisu{\figBoxA}{Arc d'ellipse}{%
\figset write(mark={.})
\figwriten 1:(2)
\figwritene 11:(2)\figwritenw 12:(2)
\figwritee 30:(2)}
\centerline{\box\figBoxA}

\bye