text: import pygame
  from pygame.locals import *
  from pygame.color import *
  import pymunk as pm
  import math, sys, random
  X,Y,Z = 0,1,2 # Easy indexing
  
  def to_pygame(p):
      """Small hack to convert pymunk to pygame coordinates"""
      return int(p.x), int(-p.y+600)
  
  def main():
      
      pygame.init()
      screen = pygame.display.set_mode((600, 600))
      pygame.display.set_caption("Joints. Just wait and the L will tip over")
      clock = pygame.time.Clock()
      running = True
      
      ### Physics stuff
      pm.init_pymunk()
      space = pm.Space()
      space.gravity = (0.0, -900.0)
      
      space.resize_static_hash()
      space.resize_active_hash()
      
      ## Balls
      balls = []
         
      ### static stuff
      rot_center_body = pm.Body(pm.inf, pm.inf)
      rot_center_body.position = (300,300)
      
      ### To hold back the L
      rot_limit_body = pm.Body(pm.inf, pm.inf)
      rot_limit_body.position = (200,300)
         
      ### The moving L shape
      l1 = [(-150, 0), (255.0, 0.0)]
      l2 = [(-150.0, 0), (-150.0, 50.0)]
      
      body = pm.Body(10,10000)
      body.position = (300,300)
      
      lines = [pm.Segment(body, l1[0], l1[1], 5.0) 
                  ,pm.Segment(body, l2[0], l2[1], 5.0)
                  ]
  
      space.add(body)
      space.add(lines)
      
      ### The L rotates around this
      rot_center = pm.PinJoint(body, rot_center_body, (0,0), (0,0))
      ### And is constrained by this
      joint_limit = 25
      rot_limit = pm.SlideJoint(body, rot_limit_body, (-100,0), (0,0), 0, joint_limit)
      space.add(rot_center, rot_limit)
      
      ticks_to_next_ball = 10
  
      while running:
          for event in pygame.event.get():
              if event.type == QUIT:
                  running = False
              elif event.type == KEYDOWN and event.key == K_ESCAPE:
                  running = False
                  
          ticks_to_next_ball -= 1
          if ticks_to_next_ball <= 0:
              ticks_to_next_ball = 25
              mass = 1
              radius = 14
              inertia = pm.moment_for_circle(mass, 0, radius, (0,0))
              body = pm.Body(mass, inertia)
              x = random.randint(120,380)
              body.position = x, 550
              shape = pm.Circle(body, radius, (0,0))
              space.add(body, shape)
              balls.append(shape)
          
          ### Clear screen
          screen.fill(THECOLORS["white"])
          
          ### Draw stuff
          balls_to_remove = []
          for ball in balls:
              if ball.body.position.y < 150: balls_to_remove.append(ball)
  
              p = to_pygame(ball.body.position)
              pygame.draw.circle(screen, THECOLORS["blue"], p, int(ball.radius), 2)
      
          for ball in balls_to_remove:
              space.remove(ball, ball.body)
              balls.remove(ball)
  
          for line in lines:
              body = line.body
              pv1 = body.position + line.a.rotated(math.degrees(body.angle))
              pv2 = body.position + line.b.rotated(math.degrees(body.angle))
              p1 = to_pygame(pv1)
              p2 = to_pygame(pv2)
              pygame.draw.lines(screen, THECOLORS["lightgray"], False, [p1,p2])
          
          ### The rotation center of the L shape        
          pygame.draw.circle(screen, THECOLORS["red"], to_pygame(rot_center_body.position), 5)
          ### The limits where it can move.
          pygame.draw.circle(screen, THECOLORS["green"], to_pygame(rot_limit_body.position), joint_limit, 2)
  
          ### Update physics
          dt = 1.0/50.0/10.0
          for x in range(10):
              space.step(dt)
          
          ### Flip screen
          pygame.display.flip()
          clock.tick(50)
          
          
  if __name__ == '__main__':
      sys.exit(main())
  