Develop a musical piece employing the provided motif and an alphabet-based structure.
X:1
L:1/8
M:6/8
K:D
['', 'FAA FAA def gfg', 'efg age']  
X:1
L:1/8
M:6/8
K:D
 (AG) |: FAA FAA | def gfg | G3 BAG | dBG AGE | FAA FAA | def gfg | age dBG | AcB A3 :: efg age | 
 dBd gdB | G3 BGB | def gfg | efg age | def gfg | bge dBG | AcB A3 :|  