Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:9/8
K:Bdor
['f3 fec', 'BcB BAF']  
X:1
L:1/8
M:9/8
K:Bdor
 f3 fec B2 E | FAA A2 F Bce |1 f3 fec B3 | BcB BAF Ece :|2 f/g/ag fec e2 c | d2 c BAF EFA || 
 B3 BAB cBA | B3 B2 c dcf | B3 BAB cBA |1 BcB BAF EFA :|2 BcB BAF Eag ||"^Last time" BcB BAF E3 ||  