Construct a music composition that complies with the designated structure and theme.
X:1
L:1/16
M:2/4
K:Bb
['BdFB DFBd fbdf BdcB', 'cB Afcf Afcf AFAc fcAF dfBf dfBf'  
X:1
L:1/16
M:2/4
K:Bb
 dc | BdFB DFBd | fbdf BdcB | cecB AFAc | agfa gfdc | BdFB DFBd | fbdf BdcB | GABc d=efg | 
 afcA B2 :|[K:F] cB | Afcf Afcf | AFAc fcAF | dfBf dfBf | dBdf bfdB | egcg egcg | eceg bgec | 
 fefa gfeg | f2fe f2 :|  