I'm not certain what you mean by "path for the plinko ball".
If you mean the path that a ball follows as it falls, see Ball.js. The 'for' loop at line 77 determines the path that a ball will follow through the pegs. Method 'step' is called each time the simulation clock ticks, and this moves the ball.
If you mean the Path (scenery node) used to draw the ball, see BallNode.js. Each ball is currently drawn as a shaded sphere.
Chris Malley
PixelZoom, Inc.