He began weaving the composite spells he did best.
Nearly transparent threads of magic, representing logic and rules, flowed from the tip of his wand.
He bound the emotional resonance frequencies of the seven pottery jars to an extraordinarily complex external source of information.
-the Daily Prophet's editorial office in London.
"I've changed the rules for determining the resonance sequence."
Douglas explained his masterpiece to Bill.
"From now on, each day's unlocking sequence will change dynamically according to the order of the initial letters of the words in that day's Daily Prophet front-page headline."
Bill tried to understand the mechanism, and a stabbing pain of overload shot through his brain.
"Wait, you mean that to open this door, we first have to know the headline of a newspaper published all the way over in London?"
"Exactly." Douglas snapped his fingers.
"And it has to be the first edition of that day's morning paper. If they publish a supplement, the password will update in real time."
"This... honestly, do you make things this difficult for your students at Hogwarts too?" Bill rubbed his temples.
Douglas shrugged and said:
"Don't worry. I've modified these emotional mechanisms. Once they crack the emotional code, they'll get this information."
"I'll set up an internal information delivery system so you can get the latest edition of the Daily Prophet first thing every day. Then the students can just buy it from you."
To make sure they could get in themselves, Douglas also made a variation on a pair of Two-Way Mirrors-two brass compasses that displayed the current correct password sequence in real time.
One was left with Bill; the other was intended for Dumbledore.
"See? A perfect closed loop." Douglas put away the compass.
"Let's see what today's headline is." Bill unfolded the newspaper and read