Book excerpt: Every major airport has a three-letter code from the International Air Transport Association. In perhaps history's greatest-ever feat of armchair travel, Nasser Hussain has written a collection of poetry entirely from those codes. In a dazzling aeronautic feat of constraint-based writing, SKY WRI TEI NGS explores the relationship between language and place in a global context. Watch as words jet-set across the map, leaving a poetic flight path. See letters take flight (and leave their baggage behind).