Ideogramic ApS develops diagramming tools that are especially tuned for use on electronic whiteboards and that are operated using gestures much like on a Palm Pilot.
Major parts of the applications are implemented in Tcl/Tk.
More information can be found on Ideogramic's homepage: [L1 ]. A profile of Ideogramic's work appears in the on-line article, "Programming UML in Tcl" [L2 ].