Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:1/4=115
M:4/4
K:F#
['A2 F2']  
X:1
L:1/8
Q:1/4=115
M:4/4
K:F#
"F#" C2 C2 A,>B, C2 |"B" D2 B2"F#" A>G F2 |"C#" G2 A2 G>E C2 |"G#7" D2 (DE)"C#" C3 z | 
"F#" C2 C2 A,>B, C2 |"B" D2 B2"F#" A>G F2 | A2 c2"D#m" F>E FG |"F#/C#" A2"C#7" G2"F#" F3 z || 
"F#" A2 F2 A2 F2 |"C#7" G>^^F G>B"F#" A2 ^F2 |"A#" A2 E2"D#m" F2 D2 |"G#7" G>F E>D"C#" C3 z | 
"F#" A2 F2 A2 F2 |"C#7" G>^^F G>B"F#" A2 ^F2 | A2 c2"D#m" F>E FG |"F#/C#" A2"C#7" G2"F#" F3 z |]  