For decades, we have watched people fiddle around with the single cordovan stitch in the ACLS. Some people keep trying until they get a stitch by chance, but they cannot repeat it. Give them enough time and there are people who will get a second stitch by chance. The third stitch was added because it takes too long to discover it a third time by chance. The odd thing that struck us was that they often recognised the correct stitch when it appeared, but they could not repeat it. The image of the correct stitch was retained in memory, but the process of producing it was not.