Although programming pictures directly in LaTeX is severely restricted, and often rather tiresome, there are still reasons for doing so.

As mentioned above the picture environment is part of standard LaTeX and it is great for simple tasks and also if you want to control the exact positioning of individual elements on a page.

A picture environment is created with one of the two commands

\begin{picture}(x,y)\end{picture}

or

\begin{picture}(x,y)(x0,y0)\end{picture}

The first pair, (x,y), effects the reservation, within the document, of rectangular space for the picture.  The optional second pair, (x0,y0), assigns arbitrary coordinates to the bottom left corner of the reserved rectangle.

Most drawing commands have one of two forms

\put(x,y){object}

or

\multiput(x,y)(DeltaX,DeltaY){n}{object}