One star, a handful of planets and Newton's rule, which is
not much but is enough. Drag across the board to fling a planet; it will
orbit, fall in, or leave for good. There is no goal beyond watching which
of the three happens. The rest of the family
is that way.
How it works
Drag from a point and release to fling a planet
from that point in the direction of the drag. By keyboard: Tab reaches the
board, arrows move the launch point, Shift moves it further, and Space
launches a planet that should orbit. Pause stops time without clearing the
board; Reset puts back the two planets it started with. Reduced motion
starts the page paused.