He named these various four-day sets "Galactic Activation Portals."
On the grid map below ARGÙELLES paired up the first and last days, days #1 and #20, along with days #241 and #260. These four days are on the 'corners ' of the 260 grid map of day shown below. If one adds up those four "weekday" numbers (1-13) the total equals 28.
1 + 7 + 7 + 13 = 28
The next 2 pairs (that add up to 28) occur in rows 2 and 12, and so on.
He designated the dark grey shaded days on the chart below as connected to "the Past" and the brown shaded days connected to "the Future."
260-Day Map with Galactic Activation Portals (G.A.P.)
Past (grey) and Future (brown)