The invention of a zipper was all that was needed to complete the categories of signs, which in a way connect Chichen Itza, the solar calendar, the pyramidal numbers, to the Phaistos disc itself. Just by zipping apart the factual units in the initial strophe: A01, A02, A03, A04, A05, A06, now belonging to side B (part B, 216 units), and leaving the abbreviated part (buttonholes) to stay on side A (part A. 150 units). Or simply imagine two layers. What matters the most for me, is not if this model complies with reality, but that it was found within the range of possibilities.