FantasticContraption

Addictive, indeed. Once you get stuck into it, it can eat time. 4:30am I was up trying to solve level 20, curse you. --AC

Done level 20 now (link below). There are many more elegant solutions in the "other players' machines" link, but this one is mine, and it gets there. Eventually. --AC

Addictive indeed.  It is 21:30 and I should have been home hours ago.  Got to level 15 though. :-)  --DR

Here's [my solution to level 20]. It was a lot easier than I expected, once I had got over failing to make a strong enough catapult. The only one I haven't solved now is level 19. Wow, Alex, your solution is ... complicated. Ah - [level 19 done]. --Admiral

Anyone have a solution to the Tube one?  The others I can work towards (I think I managed about 16) but that one I just have no clue for. --K

I could post you links to several other people's examples. I was rather frustrated to find that none of my ideas worked, and even my attempts to make things directly inspired by other people's attempts didn't work either. Tube seems to be far more sensitive to tiny details of precise positioning than other levels. --AC

So, ve haf a bug. Some of those solutions (16, 20) don't work on my computer. In 16 the crawler gets stuck, eventually knocks the cradle off the ledge and then is borne down in a torrent of balls. Iiiinteresting. --SF

How bizarre. I find that surprising. Surely it should be deterministic, unless its physics model goes down to the quantum level? --Rachael

Should be, but there's almost certainly a random perturbation added when things are moving really slowly.  Depending on how it behaves when the computer is too slow to do all the work each frame you might get different results from that too (if it slows down the frame rate and thus changes how game-time matches real time things should stay consistent, but slower.  If it instead keeps the framerate up it changes how long each time step is and thus changes the results.)  Personally, I can't say I've noticed any non-determinism - machines seem to behave the same on each run.  As an improvement, I'd like to see a version which very slightly alters the fixed terrain on each run (telling you it will do so) so that you have to try and make robust solutions rather than 'it just works' ones.  --Vitenka

Machines work the same (mostly) but there seems to be a random element about which way balls bounce.--ChiarkPerson

To the left and to the right... cue AC/DC ;) - MS

I had a bit of fun building a green trebuchet, but I lost the design due to a mis-click. --Admiral

Some people took it even further by banning all wheels. Just rods. I'm impressed at [Full-up] and [Around the Bend] the interesting way - cf [the simple way], and most of all [Unpossible]. --PT