code: def __init__(self):
      pg.QtCore.QObject.__init__(self)
  
      self.damping = 0.1  # 0=full damping, 1=no damping
      self.relaxPerStep = 10
      self.maxTimeStep = 0.01
  
      self.pos = None  # (Npts, 2) float
      self.mass = None  # (Npts) float
      self.fixed = None  # (Npts) bool
      self.links = None  # (Nlinks, 2), uint
      self.lengths = None  # (Nlinks), float
      self.push = None  # (Nlinks), bool
      self.pull = None  # (Nlinks), bool
  
      self.initialized = False
      self.lasttime = None
      self.lastpos = None
  
file_path: pyqtgraph/pyqtgraph/examples/verlet_chain/chain.py
imports: import time
  import numpy
  import pyqtgraph
  from .None import relax
label_desc: Use image node_id 1 to create a new ChainSim object from inherited base classes: pg.QtCore with example: obj = ChainSim()