This is sort of a blast from the past. Thirty years ago we were writing entire window systems in PostScript - with object-oriented classes and toolkits. Not

This is sort of a blast from the past. Thirty years ago we were writing entire window systems in PostScript - with object-oriented classes and toolkits. Not very practical but it was fun at the time. See NeWS. Owen Densmore and James Gosling were the main proponents.