During the Spring and Autumn Period (770-476 B.C.), a master craftsman named Gongshu Zi from the State of Lu, known as "Lu Ban," crafted a magpie from bamboo and wood.
He installed a mechanism inside it. When activated, the magpie could soar high like a real bird, flying continuously for three days and nights before landing.
Gongshu Zi was immensely proud of this ingenious creation.
When Mo Zi, the founder of Mohism, heard about it, he went to see Gongshu Zi immediately and said:
"As you know, an ordinary carpenter can quickly make a linchpin for a wheel using minimal wood. A cart fitted with linchpins on its axle can carry heavy loads up to 50 dan. Yet, you expended painstaking effort on this wooden magpie. Though beautiful and capable of flight, it cannot match the linchpin's practical value. A craftsman's work should benefit people's lives to earn praise for skill and cleverness. Otherwise, it risks being derided."