Each time, the mechanism could project an image of the objects from the side opposite its glowing face.
'This mechanism is pretty neat,' Milady thought with a bit of regret. 'It must be expensive, right?'
Seeing the crowd's excitement building, the middle-aged man asked with a smile, "Who else wants to take on the challenge?"
'Wait, what if I use that method...'
Milady looked at the stage, then at the shop nearby, and an idea suddenly struck her. 'Could I actually get my hands on this mechanism today?'
"I've figured it out," she said, the idea seeming more and more plausible as she considered it. Her mind made up, she called out, "It can't see through paper."
Paper hadn't been mentioned in the demonstration; perhaps no one considered something so easily torn to be a barrier.
The middle-aged man seemed to find this hilarious. "It can see through brick and stone, so why would a thin sheet of paper stop it?"
"No, I'm confident I can prove it," Milady shouted as she pushed her way through the crowd. Someone behind her laughed. "Young lady, you don't really think paper can block the mechanism, do you?"
"If you can prove it, this mechanism is yours," the middle-aged man said good-naturedly.
Milady proposed, "But just testing it plainly is no fun. Let's play a little game. Have the Chang'an people ever played 'Variables'?"
The middle-aged man had just started to shake his head when his young assistant exclaimed, "Ah! Is that the game where you each take some small items and guess how many the other person has?"
"Not quite," Milady said, confidently walking onto the platform. She picked up two of the paper boxes from the stage, handed one to the middle-aged man, then casually took out some spare change she had prepared. She gave it to the assistant and instructed him, "Could you go to the snack shop over there and buy ten pieces of candy? Remember, exactly ten."
After a questioning glance at his boss and receiving a nod, the assistant dazedly left. He quickly returned with a small paper packet, which indeed contained ten round, soft, flat persimmon candies.
"We each have five pieces of candy and one paper box," Milady said, giving half the persimmon candies to the middle-aged man. She led him to the table, and they took their positions on opposite sides.
"We can each decide how many candies to place under our box. Placing none is also an option. Be careful during this step not to let the other person see, and hide your remaining candies well. Then, we will take turns guessing a number for the total amount of candy under both our boxes."
"But my mechanism isn't for guessing," the middle-aged man said, quite pleased as he saw the crowd they were attracting grow larger.
"Correct. That's why I'll let you use the mechanism to see the candy under my box before you state a number. I, however, can only guess, and I must avoid any number you've already guessed."
"Doesn't that mean you're guaranteed to lose?" someone from the audience immediately asked.
Milady paid them no mind.
"I want to test if your mechanism can succeed two times in a row. So, after you state a total, I'll reach under my box. I might add or remove candies, or I might do nothing... After that, you'll scan it again to see how many pieces are in my box. Don't worry, I'll spread my candies out one by one to make it easy for your mechanism to scan. Only after you state your second number will it be my turn to say one. You get two guesses, but I only get one."
After confirming that everyone understood the rules, she said with a smile, "I guarantee that in the end, my guess will be right, and yours will be wrong."
"Your game isn't going to win you this mechanism!" The middle-aged man laughed. "Do you think the image presented by the mechanism has some kind of delay that will make me miscount? You're wrong. Even with multiple objects, the image is presented all at once."
"Is that so? If the mechanism makes a mistake, then you'll make a mistake."
Seeing him shake his head, as if he found her words utterly absurd, Milady said with a smile, "Then let's give it a try."
"Fine," the middle-aged man said with a nod. "If I'm wrong, I'll give you the mechanism for free."
Just as before, the young assistant operated the mechanism. Milady and the man first put the candies in their pockets, then clutched a handful and reached under their boxes to place them. They were both very careful. Milady even used one hand to shield the outside of the box, so the people in the audience couldn't see how many they'd put down, no matter how much they craned their necks.
"You can scan it now," Milady instructed the assistant.
With far more care than before, the assistant aimed the bottom of the mechanism at the paper box and moved it around. Before long, an image popped up: there were three candies inside Milady's box.
The middle-aged man smiled. "You can't guess the number I've already guessed. So even if you figure out how many candies I put down from the total I call out, you'll still have to avoid the correct sum and guess a wrong one?"
"Yes, unless you're wrong," Milady said, her hands in her pockets and her expression relaxed.