scenarios:
------------
vase on a table


chairs around the table
plates with utensils to left and right
serving platters in the center
candles in the center
cups for every plate


bookshelf against the wall
books on top of the shelf


bed against the wall
pillow at head of bed
wooden chest at foot of bed
clothes in wooden chest
small bedtable beside bed
stack of books on bedtable
light source beside bed


dresser against the wall
clothes in the dresser


desk against the wall
chair in front of desk
book on desk


(applies to crates and sacks as well)
basket against the wall
baskets beside baskets
baskets on top of baskets
ingrediants in baskets




two kinds of positioning predicates?
------------------------------------
- edge of, center of, corner of, around

- on top of, underneath, beside (same bottom z)

must supply both predicates
predicates in each category are mutually exclusive

one predicate specifies x,y positioning
one predicate specifies z positioning

edge of - outer edge of subj lines up w/ inner edge of obj
center of - x,y centers match
corner of - corner of subj matches w/ corner of obj
around - outer edge of subj lines up w/ outer edge of obj

on top of - bottom z of subj matches top z of obj
underneath - top z of subj matches bottom z of obj
beside - z's match

inside is in a class of its own, at least in this particular case

otherwise inside specifies that subj bounding box is completely within 
bounding box of obj