U' R2 U2 L2 R2 B R2 F' L2 B D2 R2 L U' L' R D2 L2 U L'
x2 // inspection
R r U' x' D2 F' R D // cross
y' U' U' R U' R' U' R U R' // 1st pair
U2' R' U2' z U' D R U // 2nd pair
z' y U' R U' U' R2' U' R // 3rd pair
U R U' R' y' U' R' U' R // 4th pair/ZBLS
U' R R D r' U' r r' U' r D' R' U2' R' U' // ZBLL