I didn’t sleep well. The air conditioner went off during the night, which meant I didn’t have to steam my suit when I got up the next morning. I got dressed and went downstairs. The programming started at nine with Abey Fields’s Wonderful World workshop in the Mary Pickford Room, a breakfast buffet in the ballroom, and a slide presentation on “Delayed Choice Experiments” in Cecil B. DeMille A on the mezzanine level.

The breakfast buffet sounded wonderful, even though it always turns out to be urn coffee and donuts. I hadn’t had anything but an ice-cream cone since noon the day before, but if David was around, he would be somewhere close to the food, and I wanted to steer clear of him. Last night it had been Grauman’s Chinese. Today I was likely to end up at Knotts’ Berry Farm. I wasn’t going to let that happen, even if he was charming.

It was pitch-dark inside Cecil B. DeMille A. Even the slide on the screen up front appeared to be black. “As you can see,” Dr. Lvov said, “the laser pulse is already in motion before the experimenter sets up the wave or particle detector.” He clicked to the next slide, which was dark gray. “We used a Mach-Zender interferometer with two mirrors and a particle detector. For the first series of tries we allowed the experimenter to decide which apparatus he would use by whatever method he wished. For the second series we used that most primitive of randomizers—”

He clicked again, to a white slide with black polka dots that gave off enough light for me to be able to spot an empty chair on the aisle ten rows up. I hurried to get to it before the slide changed, and sat down.

“—a pair of dice. Alley’s experiments had shown us that when the particle detector was in place, the light was detected as a particle, and when the wave detector was in place, the light showed wavelike behavior, no matter when the choice of apparatus was made.”

“Hi,” David said. “You’ve missed five black slides, two gray ones, and a white with black polka dots.”