def __init__(self, boardfilename, physicsfilename, draw=False, maxSpeed=None, maxPosAcc=None, maxNegAcc=None):
     Board.__init__(self, boardfilename, draw)
     if maxSpeed==None and maxPosAcc==None and maxNegAcc==None:
         self.moves = readPhysics(physicsfilename)
     else:
         try:
             file = open(physicsfilename, 'r')
             self.moves = cPickle.load(file)
         except IOError:
             self.moves = physics.getAllowedMoves(maxSpeed=maxSpeed, maxPosAcc=maxPosAcc, maxNegAcc=maxNegAcc, vis=False)
             file = open(physicsfilename, 'w')
             cPickle.dump(self.moves, file)