Manager Lin came over as well.
Yu Zhengyang pointed out two spots.
"Here, and here. The fire escape routes in these two spots are positioned too differently from those elsewhere. This floor's external dimensions aren't the same as the other floors', but the fire escape routes weren't adjusted. Whoever drew this... seems to have overlooked that."
David studied the plans for a moment, and his expression suddenly turned serious.
He raised both hands to his head. "Oh! Lin! Who drew these plans? How could they make such an elementary mistake?"
Manager Lin had spotted the problem too.
"Good heavens! I'll get someone to check this right away! Thank goodness we caught it early! There's still time to correct it!"
Holding the plans, Manager Lin started making a call.
A few minutes later, a bespectacled man of about thirty hurried in, then left with the plans, his face flushed red.
Only then did David turn to Yu Zhengyang and ask in surprise:
"Yu! I'm curious! If you didn't even recognize this symbol, how did you realize it was positioned incorrectly?"
Yu Zhengyang said sheepishly, "I didn't recognize the symbol, but I compared the positions and ranges of every instance of it. After comparing them, I found that only this floor's fire escape routes were out of alignment. This floor's external dimensions are four meters smaller. On a 1:100 drawing, that's hard to spot just by looking. You have to compare the numbers beside it. It really is easy to overlook."
"There's an allowable range for positioning fire escape routes. How did you know this one fell outside it?"
"I... I noticed that, although the other symbols were all in different positions, they stayed within a certain numerical range. That was why I hesitated just now and compared them several times. Only