Compose a musical piece in accordance with the outlined theme and structure.
X:1
L:1/8
Q:1/2=80
M:4/4
K:D
['B d>BAF AA AA/B/ d>BAF E/E/E Ec', 'D g fdfa egfe fdfa B/B/B Bg'  
X:1
L:1/8
Q:1/2=80
M:4/4
K:D
 B | d>BAF AA AA/B/ | d>BAF E/E/E Ec | d>BAF Agfe | dBAF D/D/D D :: g | fdfa egfe | fdfa B/B/B Bg | 
 fdaf egfe | dBAF D/D/D D :|  