Create a musical composition adhering to the provided thematic and alphabetical guidelines.
X:1
L:1/8
M:4/4
K:Bmin
['AB B2', 'fB B2']  
X:1
L:1/8
M:4/4
K:Bmin
|: AB B2 f3 e | AB B2 cAec | AB B2 fBde | faaf eAce | AB B2 f3 e | AB B2 cAec | dB B2 effe | 
 dBBA B2 B2 :: fB B2 fBde | faag fB B2 | eA A2 eAfA | effe cA A2 | fB B2 fBde | faag fB B2 | 
 dB B2 effe | dBBA B2 B2 :|  