"I agree." Her lip thins. "Come upstairs. There's some food left."

Occlus follows after Hohenheim.

"Did you enjoy those sweet buns?"

"I did. Were they yours?"

"My Dilraba made them," she says proudly. "She's engaged already."

They enter a small main room with a large table laden with bowls of rice. (The oven seems to be outside.) There's a mattress in the corner. On the opposite wall is a giant, ornate cabinet that smells of herbs.

Hohenheim produces a sheaf of paper from a sack on his back. "This is my gift for you -- simple medical arrays and instructions for how to use them. You should be able to use them with your needles."

She accepts it gratefully and places it carefully out of the way of the food, which they proceed to eat.

Meanwhile Hohenheim entrusts Occlus with another copy. It contains many basic elements of arrays that she has already seen in her practice.

She studies it, attempting to reconstructing the underlying logic and derive the principles.

Pentagrams seem to recur in the designs. The simpler designs seem to generally be the more difficult ones to perform.

Which implies that the detail of the design is doing some sort of work to make the alchemy easier. Better specifying the effects or the mechanism so less power is wasted, perhaps?

One of the first theory pages describe three steps: comprehension, deconstruction, and reconstruction. An elaboration on the first step explains that an alchemist must understand the structure and properties of the material to be transmuted. For some of the examples, this seems to mean knowledge of chemistry. For others, there are symbolic representations of various characteristics of chi. 

She knows the basics, but chemistry was never her focus. It's more than enough to let her follow this. The representations of chi require more thought and translation.

The clinic opens. Children bustle around the lower half of the store, sweeping and cleaning. A man brings clean linens to the back entrance. 

"I can do some basic explanations of some of the arrays, but unfortunately the easier ones are more specialized, so it may be difficult for you to find practice."

"The explanations alone will be helpful -- we should be downstairs, there's usually a line waiting before we open."

"Lead the way."

There's more traffic to this clinic than there was to the little enclosure Hohenheim set up. Their host, Adina Shahidi, tasks her children with preparing more common tinctures.

Hohenheim doesn't cure anyone directly. Instead, he waits until he notices that someone has a malady that can be cured with one of the easier arrays, and coaches Adina through using them.

Quite altruistic of him. Less useful for her purposes, but there is time to work on her other techniques.

"Here, Occlus, you should be able to do this one if you can reproduce it correctly."

The design is hideously complicated. Hohenheim explains that it's diagnostic.

That fits the 'detail is direction' hypothesis. Diagnostics need to have tests and conditions.

She is at this point well-practiced enough to accurately draw the array.

Hohenheim is pleased! "You learn quickly."

"Yes. This is relatively simple."

"Do you have a background in chemistry?"

"Not in particular, though I have never let an opportunity to increase my knowledge pass me by."