Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/2
K:Bb
['|{g} f=efg', 'AFcF DFBF CFAF BdcA']  
X:1
L:1/8
M:2/2
K:Bb
 de |{g} f=efg f2{a} b2 |{g} f=efg f2{a} b2 | dfbf cfaf | dfba gfde |{g} f=efg f2 a b2 | 
{g} f=efg f2 a b2 | dfbf cfaf | bfdf B :: F/E/ | DF (3F=EF BFdF | CF (3F=EF AFcF | DFBF CFAF | 
 BdcA BGFE | DF (3F=EF BFdF | CF (3F=EF AFcF | DFBF CFAF | BdcA B2 :|  