Displays scales and chords positions on a guitar neck:
* supports any tuning, any number of frets and any number of strings
* supports coloring tonics and other specific degrees
* all the frets or any subset can be displayed at once.

Examples:

C major scale:

 0  1   2   3   4   5   6   7   8   9   10  11  12
|3|-4-|---|-5-|---|-6-|---|-7-|-1-|---|-2-|---|-3-|
| |   |   |   |   |   |   |   |   |   |   |   |   |
|7|-1-|---|-2-|---|-3-|-4-|---|-5-|---|-6-|---|-7-|
| |   |   |   |   |   |   |   |   |   |   |   |   |
|5|---|-6-|---|-7-|-1-|---|-2-|---|-3-|-4-|---|-5-|
| |   |   |   |   |   |   |   |   |   |   |   |   |
|2|---|-3-|-4-|---|-5-|---|-6-|---|-7-|-1-|---|-2-|
| |   |   |   |   |   |   |   |   |   |   |   |   |
|6|---|-7-|-1-|---|-2-|---|-3-|-4-|---|-5-|---|-6-|
| |   |   |   |   |   |   |   |   |   |   |   |   |
|3|-4-|---|-5-|---|-6-|---|-7-|-1-|---|-2-|---|-3-|
  

E major chord (from fret 5 to 9):

  5   6   7   8   9  
|-1-|---|---|-2-|---|
|   |   |   |   |   |
|-3-|---|---|---|---|
|   |   |   |   |   |
|-2-|---|---|---|-3-|
|   |   |   |   |   |
|---|---|-1-|---|---|
|   |   |   |   |   |
|---|---|-3-|---|---|
|   |   |   |   |   |
|-1-|---|---|-2-|---|