Develop a musical composition using both the specified melodic theme and the alphabetical pattern naming.
X:1
L:1/8
M:6/8
K:Bb
['B3 B3 B>cB d>ef', 'A>GF d>ef fff f<bf fed e>fg ggg', 'B3 B3 B>cB d>ef']  
X:1
L:1/8
M:6/8
K:Bb
 B3 B3 | B>cB d>ef | B3{c} B>AB | G>cB A>GF | B3 B3 | B>cB d>ef | g>ab fed | c>dB A>GF || 
 d>ef fff | f<bf fed | e>fg ggg | (g<b)g gfe | d>ef f>ff | f>gf fga | bag fed | c>dB A>GF || 
 B3 B3 | B>cB d>ef | B3{c} BAB | G>cB AGF | B3 B3 | B>cB d>ef | g>ab f>ed | c>dB A>GF ||  