Ctwm (Claude's Tab Window Manager) was developed by Claude Lecommandeur as a modification to twm which allows the use of multiple virtual screens or workspaces, as well as the use of background images on the desktop.
Ctwm is highly configurable, and most visual and behavioural aspects of windows and the desktop can be altered.
Ctwm's configuration is specified within a file named .ctwmrc, which is read and processed by ctwm upon startup.