Sherlock Holmes Program 3A

From Memory Alpha, the free Star Trek reference.

Sherlock Holmes Program 3A was a holographic program created by Lieutenant Geordi La Forge and Lieutenant Commander Data aboard the USS Enterprise-D in 2365. It was based on Sir Arthur Conan Doyle's characters from his Sherlock Holmes stories and novels. The program was designed to create an adversary capable of outwitting Data, specifically Professor James Moriarty. (TNG: "Elementary, Dear Data")