BitSet findAtomsInRectangle(Rectangle rect) {
		bsFoundRectangle.and(bsEmpty);
		for (int i = atomCount; --i >= 0;) {
			Atom atom = atoms[i];
			if (rect.contains(atom.screenX, atom.screenY))
				bsFoundRectangle.set(i);
		}
		return bsFoundRectangle;
	}