Move the money

The workshop's plans, and the best one. The sliders change what a table and a chair sell for.

Try this. Drag the chair price up past $15. The best plan does not drift — it jumps from one corner to the next, and then sits there for a long while.

The prices are read off the rules the best plan is pressed against, and the bill is computed from them independently of the plan. That the two agree at every setting of the sliders is the whole point of chapter 5.