ok. so i see that everybody is obsessed with this game called iPhysics so i decide to check it out. ive installed it and ive installed all the level packs i found on installer. anyways, i beat the original 4 levels of crayon physics, but i seriously cant beat any level of any other pack. how do you do it? people talk about joints which are white circles you create by tapping the screen? when i tap the screen nothing happens. i dont get these "joints" also many times i cant drag objects. many levels i dont see any way to beat. are there some techniques and strategies i dont know about? are there certain shapes you can create that i dont know about?