A spring is in the air

Click mouse to place springs and try to avoid that the whole thing collapses. Build towers as tall as possible using springs!
Menu:
- up/down to select level
- enter to start level
- esc to quit
Move mouse over existing active joint (orange joints have to be activated first) to select start for new spring. Move mouse to select existing joint for end of new spring or
select place for new joint as endpoint for spring.