When most think of Fallout, they think of the iconic Vault Boy and the S.P.E.C.I.A.L. system. This was not always the case.
Originally, the first Fallout title was going to use Steve Jackson Games' GURPS system. The Generic Universal Role Play System is similar to S.P.E.C.I.A.L. with various attributes such as strength and health. After a legal dispute between Steve Jackson Games and Interplay, the rights to the system were revoked and Black Isle had to create their own system. This resulted in A.C.E.L.I.P.S. being created, which would later be rearranged to spell S.P.E.C.I.A.L.
- https://www.thegamer.com/fallout-unknown-facts-trivia/