isOpposite static method
Returns true if the quadrants are 1 and 3, or 2 and 4
Implementation
static bool isOpposite(int quad1, int quad2) {
if (quad1 == quad2) return false;
int diff = (quad1 - quad2 + 4) % 4;
// if quadrants are not adjacent, they are opposite
if (diff == 2) return true;
return false;
}