Just watch. Starting positions, masses and initial velocities generated randomly each time.
2 March 2015 Now with Newton's 2nd law! Maybe not as pretty but at least a bit more accurate ;-) 7 Oct 2013: incorporated improvement to movement taken from Bucklemon ( http://scratch.mit.edu/users/Bucklemon/ )'s remix of this project, removing jagged edges; pushed back the border edges for smoother 'wrap around' effect. JOHANN STRAUSS: The Blue Danube - Waltz. PLEASE GO TO https://archive.org/details/JOHANNSTRAUSSTheBlueDanube-Waltz-NEWTRANSFERJOHANNSTRAUSSTheBlueDanubeWaltz FOR SUPERIOR TRANSFER & HIGHER BIT RATE. Vienna Philharmonic Orchestra. Georg Szell, conductor. HMV 78rpm disc C.2686 (32-4795, 4796). Recorded June 23, 1934. Digital transfer by F. Reeder