N-Order Bezier

function lerp(start, end, bias) = (end * bias + start * (1 - bias));

function quad_p(sp, cp, ep, t) =
  // Calculates a point for a quadratic bezier curve
  lerp(lerp(sp, cp, t), lerp(cp, ep, t), t);

/*
* The first and last point in points[] are used
* as the start and end points, so give it at least
* 3 points or it'll probably break. Don't set p.
*/
function n_p(points=[], p=[], t=0) =
  // Calculates a point for an n-order bezier curve
  (len(p) == 1)
  ? p[0]
  : (len(p) == 0)
    ? n_p(p=[ for(i=[1 : len(points) - 2]) quad_p(points[0], points[i], points[len(points) - 1], t) ], t=t)
    : n_p(p=[ for(i=[0 : len(p) - 2]) lerp(p[i], p[i + 1], t) ], t=t);

function n_bezier(points, res=.1) = [
  // Generates a n-order bezier curve
  for(t=[0 : res : 1])
    n_p(points, t=t)
  ];

p1 = [
  [0, 0],
  [50, 500],
  [100, 0],
  [150, -500],
  [250, 500],
  [300, -1000],
  [350, 500],
  [400, 0]
];

for(p=n_bezier(p1, res=.01)) {
  translate(p) sphere(1);
}