No idea if others at Twitter suggested this as I can't read the thread (and have no intention to subscribe) but a nice add on would be a score inversely proportional to the travel an iceberg would need to obtain a stable floating position, with ideally the very hard goal to draw it already in a perfect stable way, waterline height included.
It isn’t too hard to get fairly close to that by drawing something that’s extremely stable, for example something very wide but not tall or an equilateral triangle, with one corner facing down.
Then, use your first attempt to correct for the correct height.
⇒ I think a good game would need some other constraint, maybe score more for max height above the surface, or for how long a polar bear can keep their feet dry while it melts (a very wide but not tall stripe will melt faster than something resembling a ball)