SimplePhysics for iPhone lets you design complex structures for everything from tree houses to Ferris wheels and then simulates your design with a sophisticated physics engine. Create your design in seconds with the blueprints editor. If you make a mistake, simply tap the Undo button. Zoom in and out by pinching the screen and pan the view using a two finger drag. While testing, you can see how the strain is distributed across your design. Areas that are under immense strain are colored bright red, while other areas are colored green. This allows you to find and fix problem areas in your design.
iPhone OS 3.x,
iPhone OS 4.x
||Compatible with iPhone, iPod touch, and iPad, requires iOS 3.0