Compose a musical piece in accordance with the outlined theme and structure.
X:1
L:1/8
M:4/4
K:D
['af f2']  
X:1
L:1/8
M:4/4
K:D
 dB B2 BAFA | D2 FA defe | dBBF AAFA | BBed egfe | dB B2 BAFB | A2 FA defg | afge fdec | 
 dBAB e2 fg | af f2 afbf | af f2 afef | af f2 a3 f | egfe dB A2 | af f2 afbf | af f2 afea | 
 fa a2 fb b2 | bafe fgfe | affb afbf | fefb afef | af f2 a3 f | egfe dB A2 | af f2 afbf | 
 af f2 afea | fa a2 f [bg]3 | [bg] afe fgfe |]  