flipdot-pattern-combinator

class Pattern:
    _points = set()
    def _init__(self, points):
        self._points = points


class Circle(Pattern):
    def __init__(self, r):
        ps = set()
        # compute every point for that radius
        # ………
        self._points = ps


def combine(pattern1, pattern2):
    return Pattern(pattern1.union(pattern2))