I wrote a series of five extremely short piano pieces called each Possible World in 2005. They last between 15 and 20 seconds each, with the exception of the slower nr. 4, which lasts around 30 seconds. Possible World 1-4 are for one piano. Possible World nr. 5 is for one, two, three or four pianos, with each pianist playing a different ordering of the same material. This particular performance by pianists Dante Boon en Samuel Vriezen was recorded in Vienna during the Wiener Tage der Zeitgenössischen Klaviermusik in 2005.