y // inspection
U r U' y U' // cross
R' U R U' R' U R U' // 1st pair
R U' R U x' U R U' z' // 2nd pair
U' U' R U' R' U' R U' R' U R U' R' // 3rd pair
R' U' R U' U' R' U' R // 4th pair
U' U' r U' U' R' U' R U' r' // OLL
U' U' R U' U' R' U' R U' U' z U' R z' R' z R' U R2