Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
Q:1/2=90
M:6/4
K:C
['C E', 'g a g f']  
X:1
L:1/4
Q:1/2=90
M:6/4
K:C
 C E C E G A | c3/2 d/ c B A G | c A A A A2 a | g a/g/f/e/ d2 c | C E C E G A | c3/2 d/ c B A G | 
 A c/A/G/E/ G A/G/F/E/ | F G/F/E/F/ D2 C || e/f/ g g g3/2 f/ g | a g f e d c | f/g/ a a a2 g | 
 c/B/c/d/e/f/ d2 c | e3/2 d/e/f/ g e g | a g f e3/2 d/ c | A c A G E G | A/B/ c E D2 C |]  