1 · The grid is made of boxes
Every STATIC mark is made of boxes. The 3×3 grid is the numpad: 7 8 9 on top, 4 5 6 in the middle, 1 2 3 at the bottom. Press a key and its box fills. A Tolu is the set of filled boxes, not the order you pressed them, so there are exactly 512 Tolus.
A filled box is a solid square. The gridlines are the same colour as the boxes, so a filled box blends into its lines. Four states follow from that:
Press the boxes, or use the numpad keys 1-9 while the pad is focused. Backspace clears.