I'm running TeXworks and MikTeX on Microsoft Windows and within a document I have the code you see below. Compiling results in a pdf file in which I can see the text within this picture but I can't see the line or the circles. Nonetheless when I print it the line and the circles are there. Is there something I can do differently to make the line and the circles visible?
\setlength{\unitlength}{0.66mm}
\begin{picture}(100,100)(0,0)
\label{picture of bitangent plane}
\put(40,50){\circle{60}} % left big circle
\put(140,50){\circle{60}} % right big circle
\put(122,74){\circle*{2}} % dot at e^{i\theta} on right circle
\put(122,26){\circle*{2}} % dot at e^{-i\theta} on right circle
\put(58,26){\circle*{2}} % dot at e^{-i\theta} on left circle
\put(70,50){\circle*{2}} % dot at -1 on left circle
\put(38,11){\line(4,3){104}} % line
\put(140,80){\circle*{2}} % dot at i on right circle
\put(140,20){\circle*{2}} % dot at -i on right circle
\put(170,50){\circle*{2}} % dot at 1 on right circle
\put(110,50){\circle*{2}} % dot at -1 on right circle
\put(10,50){\circle*{2}} % dot at 1 on left circle
\put(40,80){\circle*{2}} % dot at i on left circle
\put(40,20){\circle*{2}} % dot at -i on left circle
\put(58,74){\circle*{2}} % dot at e^{i\theta} on left circle
\put(116,76){$e^{i\theta}$} % right
\put(115,19){$e^{-i\theta}$} % right
\put(62,76){$e^{i\theta}$}
\put(59,19){$e^{-i\theta}$} % left
\put(173,49){$1$} \put(5,49){$1$}
\put(101,49){$-1$} \put(72,49){$-1$}
\put(140,83){$i$} \put(40,83){$i$}
\put(137,14){$-i$} \put(35,14){$-i$}
\put(70,5){\text{The bitangent plane.}}
\end{picture}