I would like to place a series of lines using the picture environment in latex but I can to placement of those lines to be relatively placed not absolutely place; i.e. I want to have defined coordinates that I can build off of. 

Basic example of absolute placement:

```
\setlength{\unitlength}{0.75mm}
\begin{picture}(60,40)
\put(20,20){\line(5,2){1}}
\put(30,20){\line(5,3){1}}
\end{picture}

```

Basic example of relative placement (what I would like):

```
xc=20

\setlength{\unitlength}{0.75mm}
\begin{picture}(60,40)
\put(xc,20){\line(5,2){1}}
\put(xc+10,20){\line(5,3){1}}
\end{picture}

```

Does anyone have any suggestions?