"What is this?"
When Lucius arrived at Kraft's attic, he found patchy color maps pinned all over the wall, stretching from the corner to the door.
Small, adjoining squares filled the black-and-white maps, with narrow, winding gaps running between them. Most of the squares nearly blended together, but a closer look revealed differences in the density of the diagonal hatching inside them.
At that, Kraft showed him the thick stack of papers in his hands. They were the results of their work over the past half month. "I filled these in on the map. Showing it as an image should make things a little more intuitive."
"White means improvement?" Lucius studied the map for a while and asked.
"No, it's the opposite. Black means improvement."
Kraft handed Lucius the record sheet and pointed to the small crosses and horizontal lines on it. "I call the ones with crossed vertical and horizontal lines positive effects, and the ones with a single horizontal line negative—or no effect. The names don't really matter, though. Just remember that the former should be shaded black on the map to show the degree of improvement."
"Each time there's one more, I add another diagonal line to the corresponding square. Since they don't have accurate timekeeping tools and have to rely on subjective judgment, the reliability of this data..."
Lucius scratched his head. He couldn't think of anything more accurate than a patient's subjective feelings. By the simplest logic, weren't people the ones who knew their own bodies best?
Kraft flipped through several pages of records and pointed out the odd ones from the past few days. "These few have changed a lot every day, and keep jumping back and forth. It's possible that the changes are real, but they're a bit too extreme."
"Look at this