def evolve(block):
    """
      Evolves the passed block given by the rules

      Args:
        block: a 2x2 matrix to be evolved
    """
    # Get sum of block
    value = sum(block[0]) + sum(block[1])
    if value == 1:
        # Return that it is a gas if there is only 1 cell with gas in it
        return 1
    else:
        # If there is not only 1 cell with gas in it, return that there is no gas
        return 0