R' F' R2 U' D R' B2 U' R B2 U F2 U R2 U' R2 F2 U' R2 F2
z x // inspection
r' U' R F' U' D R' F R // xcross
U' R' U' R U' R' U R // 2nd pair
D R U' R' U R U' R' U' D' // 3rd pair
U R' r U' R U R' U r' R // 4th pair/ZBLS
U' R2 D' R U' U' R' D R U' U' R U // ZBLL