## Octave signs
Octave signs can be attached to single units, or to a group of units.
### 1. Octave signs for single units
Let's see how we can add an octave sign to a single unit:
You can also use different wording, like instead of `up` and `down` you can write `higher` or `lower`:
Vertical of octave signs are always adjusted, but you can correct it regardless:
### 2. Octave signs with brackets
We can declare octave sign like other elements that connect sound units:
Like octave signs for single units, you can correct vertical position of octave signs with brackets:
Like for slurs, you can decalare all octave signs after you declared all measures:
Unit coordinates for octave signs work absolutely in the same way as for slurs:
1. If a `line` is not specified after `octave` key word, then it applies to the last declared line before `octave`.
2. If you don't specify `measure`, `stave` and `voice` after `octave` key word, it always assumes that you mean `first measure`, `first stave` and `first voice`.
3. You can specify only `measure` and `stave` coordinates along with `unit` coordinate(like `first note in first measure, in second stave`). You cannot set `voice` along with `unit` coordinate, only right after `octave` key word to set a voice to whole octave sign, because octave sign is not a cross-voice element. And you cannot set `line` coordinate along with `unit` coordinate, because each octave sign must be delcared for each line where it is located. This separation allows of coordinates to set rules on behaviour of octave signs more clearly.
4. If you specified `measure` and `stave` for first unit in a octave sign, and those coordinates don't change for other units, then you don't need to repeat them.
**P.S.:** You can use numbers from 1 to 10 as words. For example, `1` is `first`, or even `1st`. We could've made possible that all numbers can be expressed as words, but unfortunately it would slow down highlighting in the editor and rendering the image. So, it was decided to enable this feature only for numbers from 1 to 10, since majority of times only these numbers are used and moreover it's easier just to type numbers as numbers. But you still can write `11` as `11th`. When you type numbers to declare coordinates (like `line`, `measure`, `stave`, `voice`, `chord/note/unit`), you can put them before or after those key words, like for example: `first measure` or `measure 1`.
Read next: Articulations
