Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/4
M:3/4
K:Bb
['B A G G3 F3', 'B A G']  
X:1
L:1/4
M:3/4
K:Bb
 F | B3 | B A G | G3 | F3 | d3 | d c B | (c3 | c3) | B2 B | B A G | G3 | F3 | d F d | d c A | B3 | 
 B2 z || G ^F G | B A G | D3 | B3 | G ^F G | B A G | (d3 | d3) | G ^F G | B A G | =F3 | B3 | 
 A c B | A G A | (B3 | B2) |]  