Ban Xia sat on the steps at the entrance of the apartment building, holding a slender, withered bamboo pole, one end in her hand and the other resting beside her foot, humming a song leisurely and squinting one eye, checking whether the bamboo pole was straight enough.
Next, she tied a one-meter-long white plastic strip to the end of the bamboo pole, and while busy with her task, she occasionally looked at the thin bamboo poles stuck in the lawn across from her. The breeze fluttered the ribbons tied to the poles, and she watched them for a while before burying her head back down and resuming her work.
After tying the strip securely, she carried the bamboo pole upstairs and erected it in the attic.
She had already set up five or six such poles. Holding a small notebook and a pencil in her hands, she checked four times a day, and then noted in the notebook:
"December 10.
8:32 AM, southeast wind, level two.
12:02 PM, northeast wind, level three.
