When I first saw this a few years ago I was not convinced that it was a piece of public art so I catalogued it as an item of street furniture associated with the kid's play area.
I suspect that there was coloured glass in the holes [in the artist's catalogue there is glass]
recently Galway City has lost its status as a ‘clean’ city in a survey of forty urban areas in Ireland. The survey found that the Millennium Children’s Park behind Galway Cathedral was “completely destroyed by graffiti on every available surface”.