Jack understood; he suffered himself. “Your timing is perfect, Dud.” Now he had at least one Christmas gift for Gia she wouldn’t be expecting. “I’ll do a dub and get it back to you as soon as…” Jack hesitated, feeling bad about asking Milkdud for another favor after he’d found Gia’s movie for him, but he had no choice. “And… I need your help.”

“Your message mentioned a building hack.”

“Right. I spotted your squiggle in the Hand Building last night.”

Milkdud’s eyes lit as he smiled. “The Hand Building… the twenty-five story ferroconcrete on Forty-fifth. Yeah, she’s a beauty. A prime example of postwar urban architecture. My handle’s still there? Cool. Hacked her about three years ago. Should’ve brought my notes, then I could give you the exact date and some details. A very cool place. That lady’s full of blind spaces.”

“You keep notes?” Jack said. This was great news. “Like some sort of hacking diary?”

“I like to think of it simply as ‘exploring.’ We were calling it ‘hacking’ back in the seventies, but then the computer geeks co-opted the term. I don’t like the comparison. Computer hacking implies mischief, malevolence, and malfeasance.”

“Not in its pure form,” Jack said.

“True. The pure computer hacker is an explorer. He wants to gain entry, open all the doors, find all the hidden places, learn all the secrets, and leave everything pretty much as he found it. That’s what I do. I get into a building and explore all the spaces the workaday occupants never see, don’t even know exist, then I get out.”

“But not without leaving your ‘Killroy-was-here’ squiggle.”

Milkdud smiled. “Which, in a bow to CB culture, we call a ‘handle.’“

“How the hell did you ever get into this?”

A shrug. “It’s sort of a rite of passage at MIT.”

“For everyone?”

“Hell, no. It’s got its dangers. First off, you can get killed. We use roofs and elevator shafts a lot, and those shafts are dangerous. Second, it’s illegal. You may not mean any harm, but try explaining that to the Man. At the very least, it’s trespassing. At worst, it’s attempted robbery. And you’d better not be claustrophobic, because your hallways are air shafts and ducts.”

Jack nodded. “I can see how that might weed out quite a few.”

“Better believe it. And add to the weeds all the ones who just don’t get it.”

Jack slapped the side of his head. “You’re kidding. You mean there’s actually some people out there who don’t think crawling through air shafts is cool fun?”