Referring to the three-way “FORTRAN” syntax, you say, “The three-way "if" was more powerful than just checking for a negative, but was probably more confusing,” this is not right. As a 15-year-old at Stuyvesant, in 1966, learning FORTRAN 4, I assure you it was the most natural thing in the world. Especially instructive was the fact that usually two of the target statement numbers would be the same. FORTRAN 4 didn’t have Boolean data types, OR, or AND and += was still in someone’s nightmare.

Note also that when Microsoft put IF( , , , ) into Excel, the most widely used computing application in the world, they essentially used this syntax.