Stuart Devlin’s Sculpture   Modern coins the sizes of shine swept off my friend’s bureau in Ghent and pocketed by my careless habit— not brown pennies too dull to return   they include designer Devlin’s sculpture of the duckbilled animal swimming up to the top swirl and five kangaroo tails mixed to a dollar.   When the Irish attained their republic they mounted their noble beasts trim, each well inside a knurled rim and labelled in lapidary Gaelic   while our successors simply enact themselves: the lyrebird lapped under music, echidna belly-on like a buckle each numerally off centre and…