flipVertical method
Implementation
SquareSet flipVertical() {
const k1 = 0x00FF00FF00FF00FF;
const k2 = 0x0000FFFF0000FFFF;
int x = ((value >>> 8) & k1) | ((value & k1) << 8);
x = ((x >>> 16) & k2) | ((x & k2) << 16);
x = (x >>> 32) | (x << 32);
return SquareSet(x);
}