C26 It Was Boring but Interesting

Zhao Lin stood outside the door, careful not to disturb Elder Wang Kan. He observed Wang Kan's hand gestures intently. Wang Kan was muttering under his breath, and with a flick of his finger, the flame in the furnace would fluctuate—now large, now small, shifting from golden to red, and then to a bluish-green. After two hours, Wang Kan was completely drenched in sweat