The two went to the Meteorology Bureau. The experts had worked out a mathematical model to estimate the starting point of the balloon. After they had calculated, Chen Shi was given a rough range. Chen Shi picked up the map and said, "This is too large. It’s almost an entire district."

The experts said, "We can’t help it. The air flow at high altitudes is unpredictable. It’s impossible to accurately infer the coordinates, and the fact that so many balloons fell at different locations in the city means that they weren’t released at the same time. Between the first and last balloon, the interval could have been a whole night, or it might have just been within an hour. We calculated with the inclusion of all the margins of errors and we got such a large range."

"Were the winds chaotic that morning?"

"Very."

"If you were a murderer, what strategy would you use to fly the balloon...