00:11:00 <zzo38> The feature added today is the (Control) block, which defines a global control object which is not in the playfield.
00:13:48 <zzo38> Such an object can never be created, destroyed, moved, or displayed on the screen, but can still receive broadcast messages, etc. This means that it is possible to have global keyboard functions or turn-based actions regardless of what other objects might or might not have.
00:15:11 <zzo38> I think I had found all of the places where these condition might be violated and where it already assumes X and Y coordinates are greater than zero, in order to avoid out of bound access or segfaults or other problems, but maybe I might have missed some.