Creativity has helped set a prisoner free three years ahead of time.

Yu Tigang was sentenced to 10 years in prison for intentional injury in 2003.

During his prison time, his cellmate's complaint about no heels in the cotton slippers inspired an invention.

Yu invented a kind of double-purpose shoe to meet different needs. With a smart design of zipper in the back, the shoes can be used as slippers or shoes with a heel added.

Some local shoemakers have expressed interest in his invention for which he was granted two patents.

After he was set free in June, Yu applied for another patent for a wind power generator.

(Source: China Daily)