My problem is to inverse 2 patterns in only one1 sed command.
Let's considered this text file :

```
LAYER M1
DIRECTION HORIZONTAL
END M1
LAYER M2
DIRECTION VERTICAL
END M2

```

So I want to invert HORIZONTAL / VERTICAL words pattern in one pass like this :

```
LAYER M1
DIRECTION VERTICAL
END M1
LAYER M2
DIRECTION HORIZONTAL
END M2

```