# CFOP step 4: 2-look PLL, finish the cube

The top is all yellow. PLL means **permuting the last layer**: moving the top pieces to their places without turning them. Full PLL has 21 algorithms. **2-look PLL** uses 6:
1. Place the corners: A-perm or Y-perm.
2. Place the edges: Ua, Ub, H or Z.

> 3D demo, Z-perm: two pairs of neighbouring edges swap: `M' U M2 U M2 U M' U2 M2 U'`

## First look: the corners

Look at the top row of each side for **headlights**: two corner stickers of the same colour on one side.

### Headlights on one side: A-perm

The algorithm from the beginner method. Put the headlights at the **back** and do it once. Then turn the top: the corners all line up.

> 3D demo, A-perm: R' F R' B2 R F' R' B2 R2: `R' F R' B2 R F' R' B2 R2`

### No headlights anywhere: Y-perm

Two diagonally opposite corners need to swap. The Y-perm does it from any angle, then turn the top to line the corners up. It's long, so learn it in two halves: `F R U' R' U' R U R' F'`, then `R U R' U' R' F R F'`.

> 3D demo, Y-perm: F R U' R' U' R U R' F' R U R' U' R' F R F': `F R U' R' U' R U R' F' R U R' U' R' F R F'`

### Headlights on all four sides

The corners are already in place. Turn the top to line them up and go to the edges.

## Second look: the edges

The corners are in place. Look at the middle sticker of each side's top row.

### One side solved: Ua or Ub

Put the solved side at the **back**. If the front edge needs to go **right**, do Ua. If it needs to go **left**, do Ub. Both are from the beginner method.

> 3D demo, Ua: R U' R U R U R U' R' U' R2: `R U' R U R U R U' R' U' R2`

> 3D demo, Ub: R2 U R U R' U' R' U' R' U R': `R2 U R U R' U' R' U' R' U R'`

### No side solved, opposite edges swap: H-perm

Every edge sits opposite where it belongs: the front edge has the back colour, and so on. The H-perm uses `M`, the middle slice, and works from any angle.

> 3D demo, H-perm: M2 U M2 U2 M2 U M2: `M2 U M2 U2 M2 U M2`

### No side solved, neighbouring edges swap: Z-perm

Each edge belongs on a side next to it. Hold the cube so the front edge belongs on the **left**: then the left edge belongs at the front, and the right and back edges swap too.

> 3D demo, Z-perm: M' U M2 U M2 U M' U2 M2 U': `M' U M2 U M2 U M' U2 M2 U'`

**No time to learn H and Z yet?** Do Ua with any side at the back. One side becomes solved, and you finish with Ua or Ub.

## Common mistakes

- **Headlights at the front.** The A-perm needs them at the back.
- **Turning the top between the two looks.** That's fine, and often needed: line the corners up first, then read the edges.
- **Slice moves the wrong way.** `M` turns like `L`: the front column goes **down**. `M'` goes up.

Source: https://scanmycube.com/learn/cfop/two-look-pll