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Hu Jing casually picked up the stack of papers; the one on top only had a few lines of simple characters that seemed to record several types of materials. As he flipped through, he saw that one of the papers depicted something resembling wheels.
Instantly, Hu Jing thought of the children's carts Jinrong had sent to her nephews in the capital. He looked closely but couldn't figure out the mechanism, while he was sure they were definitely not wheels for carts.
"What is this drawn here?" Hu Jing pulled out the sheet and handed it to Qi Younian.
Qi Younian took it over, "Ah, these are pulleys. We've used them before, mostly wooden ones. Ye Zi said that if we get blacksmiths to finely forge a few iron ones, they would last much longer and save more effort. If several are combined together and a sturdy frame is put up when building high structures, it'll be very convenient and save a lot of effort to lift things up."