An early drawing of the drawing instruments when I was working on the chassis that eventually supported instruments One, Two and Three. The instrument was designed to hold a Czech made bell jar. I will post a picture of one of these chassis with the intended glass dome. I subsequently chose 18th c. French domes that were larger and lighter (as you see on Instruments Two and Three and will be incorporated in the current instruments) and later from second hand clocks.
The instruments at this stage work between a vertical drawing on the wall and a horizontal one on the table. The observer can work with the vertical drawing through a headset fixed to a bracket on the wall. At this stage the folding picture plane is separated from the drawing instrument chassis.
At the time I was milling out the patterns for the instrument and the drawing was made as an illustration to show a group of colleagues (in a discussion group) what the pieces might look like when assembled. The characters and their condition were related to a story known to some of those in the group.