Finally began to work on the query side of Thor. Added a view/query mode switch button (yes, modal interfaces are bad, will fix this later), and a simple drawing tool so that queries can be specified. I then began to work on what I thought would be the simplest attribute possible, average angular separation between points. This would let me differentiate between circles (low separation) and rectangles and other angular shapes (high separation).
Unfortunately, though the separation computing works, my simplification function managed to spontaneously break itself, and the (recorded) difference between circles and rectangles is very small. This isn't helped by the fact that it's very hard to draw straight lines with a mouse, and so my rectangles aren't really any simpler than my circles.