Prints the Pixy blocks data.

def print_pixy_blocks(blocks):
    """ Prints the Pixy blocks data."""
    print("Detected " + str(len(blocks)) + " Pixy blocks:")
    if len(blocks) > 0 and not "signature" in blocks[0]:
        print("Something went wrong.  This does not appear to be a printable block.")
        board.shutdown()
        return
    for block_index in range(len(blocks)):
        block = blocks[block_index]
        print("  block {}: sig: {}  x: {} y: {} width: {} height: {}".format(
                block_index, block["signature"], block["x"], block["y"], block["width"], block["height"]))