Which hat? (from Slovenia)

     For a long time I have highly valued the work of Eastern European poets -- including Wislawa Szymborska, Miroslav Holub, Nichita Stanescu, Nina Cassian -- and have been pleased to find mathematical imagery in their work.  Early in November I had the privilege of attending a reading at the Goethe-Institut Washington that featured Slovenian poet Aleš Šteger -- born in 1973, winner of many awards, and described as the most translated Slovenian author of his generation.  A fun event -- from which I give you one of his slightly-mathematical offerings.

     Hat     by   Aleš Šteger (trans. Brian Henry)

     Who lives under the hat?
     Under the hat, which are three?
     Three hats.