These images are courtesy of the Crossfire Developers. More box, and wall style images can be found in Anthony's Icon Library, under the section "Programming, Walls". This specific walls were converted from Thin Walls.
<-- This structure is made up of 9 separate bitmaps
<-- Similarily this is a line of three bitmaps. Build it to any length.
This is an example
<-- Space, Dot, Space
Total number of bitmaps used above is 17, not counting 'space'. Anyone for a HTML Maze?