This is my reference drawing for the First Customer Ship version of Medusa on Unix.
At the time we started this we had to invent our own method of navigating the menus, there were no pop-ups, no lists of commands. Everything was visual except that command prompts would appear just above the list of 4 previous commands at the bottom of the screen. Each menu button had its own cursor which inverted the pixels in the menu field it was in. If the user wanted to repeat a command the button was simply clicked. To use a different command the mouse button was pressed and dragged. Some commands brought up a new selection of menus and the button cursor was placed on the most likely field to be wanted next. There was extensive logging of user actions built-in, so I had a good idea of what would follow.
The screen were monochrome then, so colour could not be used and the individual icons had to be bigger than they are today.
Bitmap editors were in their infancy so I wrote a menu and icon generator in LCIS (Bacis-1 as it later became) which took everything from a specially formatted Medusa drawing.