Drop 2, Drop 3 and Drop 2-4

For seventh chords Fretly draws the standard voicing families:

• Closed — all four tones packed within an octave.
• Drop 2 — the second-from-top voice dropped an octave.
• Drop 3 — the third-from-top voice dropped an octave.
• Drop 2-4 — both the second and fourth voices dropped.

Switch families from the voicing selector; the shape redraws in place.