Charles Babbage designed two computing engines--the Difference Engine, and the far-more-complex Analytical Engine. Neither one was ever manufactured until a complete Difference Engine was built in 2002; though Babbage did build a small working model with a limited number of digits. Also, Ada Lovelace had no hand in designing Babbage's computing engines--she appears to be the first person to see their potential to do more than generate mathematical tables, and she wrote what is arguably the first computer program in anticipation of them, but the design of the hardware was Babbage's, not hers.