A Dorian scale on the guitar fretboard
The A Dorian scale is made of A (the root), B (major second), C (minor third), D (perfect fourth), E (perfect fifth), F# (major sixth) and G (minor seventh). The fretboard shows every one of them across the neck in standard tuning (E A D G B E), and plays them back so you can hear the scale.
The Dorian mode is a minor scale with a raised sixth, the second mode of the major scale. It uses the same notes as a major scale a whole step below, so the neck shows one shape under two names. It sits between the natural minor and the major scale in colour.