We live inside most of the time, and hang up posters (or wallpaper), and decorate the inside of our huts. In the olden days (!) people lived mainly outside and decorated their surroundings. Because we're internally domesticated we can't understand the old ways. Try and analyse a William Morris wallpaper print - or a James Cauty poster - and you'll not get very far. Their social context can only be inferred. They're just a hundred years and a hundred days old, say. The problem isn't in understanding them - it's in preserving them. What's left are dissolving, being crushed or worn down.