%mathpiper,def="II"

//
// II is the imaginary number Sqrt(-1), and remains that way.
// The difference is it isn't converted to the form Complex(x,y).
//

10 # II^n_IsNegativeInteger <-- (-II)^(-n);
20 # (II^_n)_(IsEven(n) = True) <-- (-1)^(n>>1);
20 # (II^_n)_(IsOdd(n)  = True) <--  II*(-1)^(n>>1);

%/mathpiper