Letters from X was composed in 1981, Fax from X in 2003, and For 51 to LI in 2009. Not only the instruments but also the performers - all three works are dedicated to Zoltán Gyöngyössy and István Lukácsházi, and they were the first to perform them - connect the three duos, which were composed with rather long intervals between them. A duo for flute and double bass is rather unusual, yet that is precisely why it can suit the chamber repertoire of both instruments. The three pieces can also be played independently.