If these books have APL adjustable rank ⍤ used on the `for` function, we can make many more combinations: "J for⍤0 0⊢ C Programmers" ≢ J for C programmers.

If these books have APL adjustable rank ⍤ used on the `for` function, we can make many more combinations: "J for⍤0 0⊢ C Programmers" ≢ J for C programmers. "J for⍤1 0⊢ C Programmers" ≢ J++ for C programmers. "J for⍤0 1⊢ C Programmers" ≢ J for C++ programmers. "J for⍤1 2⊢ C Programmers" ≢ J++ for C# programmers. "J for⍤2 2⊢ C Programmers" ≢ J# for C# programmers. etc. Then with `commute` ⍨ we can swap the argument order as well: "J for⍨⍤1 0⊢ C Programmers" ≢ C++ for J programmers. etc. (Assuming C has a single implicit plus, C++ is a 1D array of plusses, C# has a 2D matrix of plusses)