The first thing is a limitation of the physics engine. The way physics based games work is in discrete time steps. If you chuck something very quickly at a wall, sometimes it will be one side of the wall at one point in time, and then at the next step of the simulation, it'll be the other side of the wall. The physics engine has no way to know that you should have hit the wall in the intervening time.

You can pull this off in lots of places in World of Goo, and indeed other physics games. The irony of course is that the slower your computer, the more "cheating" you can do. Indeed in Jingle Balls we had to make the walls of the "gift box" incredibly thick to help prevent balls getting thrown inside.

I think building goos outside the box isn't a bug, that whole area is just a little bit of fun

-davidc

I know the trick of throwing through objects in WOG. The amazing thing is that in MOM the applications window gets halfway in (or out) as the case may be. You cannot do this elsewhere in WOG. Either you are wholly in or wholly out not inbetween. [Except where there is a gap between two surfaces, then you can throw an object into the gap. Impossible to get it out again though!] Here is a pic showing the halfway state and the building of goos outside the box.:-

http://img127.imageshack.us/my.php?image=mombug.jpg