There are only two cases of the parity of three integers in a Pythagorean chord: 1, where all three are even 2, one is even and two are odd. Reason: Even parties are even and odd parties are odd. The sum of two even numbers or two odd numbers is even, and the sum of an odd number and an even number is odd. If they are all odd numbers, then the square of the hook+the square of the strand = odd number+odd number = even number, and the square of the string = odd number is untenable. If there are two even numbers and an odd number, then there are two possibilities: 1, the chord is odd, the pythagorean is even, then the square of the hook+the square of the strand = even+even, and the square of the chord = odd.