#### 4.3.2 Constructing a tweak

The general procedure of changing output, that is, entering a command like

                 \override Voice.Stem #'thickness = #3.0

means that we have to determine these bits of information:

- the context: here `Voice` .
- the layout object: here `Stem`.
- the layout property: here `thickness`
- a sensible value: here `3.0`

We demonstrate how to glean this information from the notation manual and the program reference.

The program reference is a set of HTML pages, which is part of the documentation package. On Unix systems, it is typically in /usr/share/doc/lilypond. If you have them, it is best to bookmark them in your webbrowser, because you will need them. They are also available on the web: go to the LilyPond website, click “Documentation”, select the correct version, and then click “Program reference.”

If you have them, use the local HTML files. They will load faster, and they are exactly matched to LilyPond version installed.

Read comments on this page, or add one. This page is for LilyPond-2.2.5 (stable-branch).