How to speed up python's 'turtle' function and stop it freezing at the end

Question

I have written a turtle program in python, but there are two problems.

1. It goes way too slow for larger numbers, I was wonder how I can speed up turtle.

Answer 1

For reference, turtle being slow is an existing problem. Even with speed set to max, turtle can take quite a long time on things like fractals. Nick ODell reimplemented turtle for speed here: Hide Turtle Window?

import math

class UndrawnTurtle():
def __init__(self):
    self.x, self.y, self.angle = 0.0, 0.0, 0.0
    self.pointsVisited = []
    self._visit()

def position(self):
    return self.x, self.y

def xcor(self):
    return self.x

def ycor(self):
    return self.y

def forward(self, distance):
    angle_radians = math.radians(self.angle)

    self.x += math.cos(angle_radians) * distance
    self.y += math.sin(angle_radians) * distance

    self._visit()

def backward(self, distance):
    self.forward(-distance)

def right(self, angle):
    self.angle -= angle

def left(self, angle):
    self.angle += angle

def setpos(self, x, y = None):
    """Can be passed either a tuple or two numbers."""
    if y == None:
        self.x = x[0]
        self.y = x[1]
    else:
        self.x = x
        self.y = y
    self._visit()

def _visit(self):
    """Add point to the list of points gone to by the turtle."""
    self.pointsVisited.append(self.position())

# Now for some aliases. Everything that's implemented in this class
# should be aliased the same way as the actual api.
fd = forward
bk = backward
back = backward
rt = right
lt = left
setposition = setpos
goto = setpos
pos = position

ut = UndrawnTurtle()