They're best described, in the author's phrase,
As "sketches, studies or what do you call them?"
Per Duckworth forward and back you trek;
You may book right through or choose between a
Peep at Perim or Chapultepec,
Sahara, Hampstead or Argentina.
You may halt, if you will, at phalansteries,
Where Mescaleros on maturangos
Eat or drink (whichever it is)
Baked tortillas and twang changangos.