Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:C
['[M:9/8][K:G] a e age .added e ecd', 'E2 d gdg gag fed edB gab']  
X:1
L:1/8
M:4/4
K:C
[M:9/8][K:G] a e age .added e ecd edg bgeveg bac G[Q:1/8=150] .D | GAG Gge dBG | ABA ABd e2 g | 
 GAG gfe dBG | ABc BAG E2 :| d | gdg gag fed | edB gab a2 b | gab abg fed |1 efg dBG A2 :|2 
 efg dBA G3 |]  