Graphical raycaster

Now that a terminal-based raycaster has been finished, it shouldn't be difficult to have a graphical demo

Start by reading the existing terminal-based raycaster and the repository entry points to understand how raycasting is currently exposed. Identify the graphics path and determine the intended demo scope before implementation. Done means the raycaster has a working graphical demo that complements the finished terminal-based version.

Written by the indexing model from the issue text.