Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:1/4=110
M:2/4
K:C
['Ad de fe dc BA Bd', 'A/A/ BA FA/A/ BA Fd/d/ ed cB']  
X:1
L:1/8
Q:1/4=110
M:2/4
K:C
 C |[K:D]"^by H.R.Bishop, 1816" F/G/ | Ad de | fe dc | BA Bd | BA FF/G/ | Ad de | fe dc | BA Bd | 
 ed d :: A/A/ | BA FA/A/ | BA Fd/d/ | ed cB | B2 Ad | dc ce | ed df | fe dc | e2 d :|  