Chord Chain for playing the custom chord progression. Chord Construction Algorithm that can make over 1000000 Fretboard Chords. 4 tunings and 3 instruments available. Guitar: E2-A2-D3-G3-B3-E4. Guitalele: A2-D3-G3-C3-E4-A4. Ukulele Low G: G3-C3-E4-A4. Ukulele High G: G4-C3-E4-A4. ▷ Three types of the 3D-Hand Model for displaying 3D-Fingering Model. Transparent. Skinned.