z x2 // inspection
U' x U U R r z L2' // cross
R' U' R' U R' U' R U // 1st pair
x' R U' R U R' l' U R U' // 2nd pair
x' R x' R2 U' U R' U' R2 U l' U R U' // 3rd pair
x2' R2 U' R2 U R2' U' R U // 4th pair
z' R U R' U R U' R' U' R' F R F' // OLL
R U R' F' R U R' U' R' F R2 U' R' U'