code: def neuron(layer_name, channel_n, x=None, y=None, batch=None):
    
    def inner(T):
      layer = T(layer_name)
      shape = tf.shape(layer)
      x_ = shape[1] // 2 if x is None else x
      y_ = shape[2] // 2 if y is None else y
  
      if batch is None:
        return layer[:, x_, y_, channel_n]
      else:
        return layer[batch, x_, y_, channel_n]
    return inner
docs: Visualize a single neuron of a single channel.
  
    Defaults to the center neuron. When width and height are even numbers, we
    choose the neuron in the bottom right of the center 2x2 neurons.
  
    Odd width & height:               Even width & height:
  
    +---+---+---+                     +---+---+---+---+
    |   |   |   |                     |   |   |   |   |
    +---+---+---+                     +---+---+---+---+
    |   | X |   |                     |   |   |   |   |
    +---+---+---+                     +---+---+---+---+
    |   |   |   |                     |   |   | X |   |
    +---+---+---+                     +---+---+---+---+
                                      |   |   |   |   |
                                      +---+---+---+---+