Construct a melodic piece using the designated alphabetic pattern and the provided musical theme.
X:1
L:1/8
Q:3/8=100
M:6/8
K:F
['F2 c A/B/cA GEG B2 G A/B/cB', 'cAF B2', 'fed cBA', 'cAF B2']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:F
 F2 c A/B/cA | GEG B2 G | A/B/cB AGF | GEC F3 || f3 fga | gec d3 | def cAF | GEG B2 d | cAF B2 G | 
 cAF B2 d | cAF B2 A GFE F3 || fed cBA | fed cBA | fed cBA | GEG B2 d | fed cBA | Bcd efg | 
 fed cBA | GEG B2 d || cAF B2 G | cAF B2 d | cAF B2 A | GFE F3 |]  