Characters on characters on characters [1000-character short story #001]

When I went to pour a coffee refill, a woman had a notebook spread out, a planner placed on top of that, and a sticky note on top of that, and she was writing characters onto it.
Both the notebook and the planner were filled with dense writing, and the sticky note was also almost completely covered in characters.
The sticky note wasn't one of the thin, long ones, but a larger, square one.
She wasn't scratching away, but rather poking at the paper as she wrote. The poking sound was likely because the pen tip was very fine.

"Would you like a refill?" I asked.
"Yes, please," she replied.
"Would you like sugar or milk?" I asked.
If she said sugar, the next branch would be regular sugar or sugar-free.
"Just milk, please," she said.

When she gets up to go to the restroom, she doesn't leave her notebook or planner behind like most customers do. Naturally, not her smartphone either. If anything, not even her bag. She leaves a piece of cloth. In winter, a jacket. In summer, a thin shawl to ward off the air conditioning.
Perhaps she really wants to take everything with her to the restroom. But she likely worries that if she leaves only the dishes at the table, they will think she has already left and clear them away.

I have gone to pour her coffee many times, and whether it's for a refill or when she declines, she is always poking away at her notebook, but the timing of characters on characters on characters, like that day, doesn't come around very often.
I try rotating the notebook, planner, and sticky note that she had stacked so neatly in my mind, alternating them. The sound of a mainspring.