FORT WORTH — If anyone had any doubt that the piano is just as appropriate a symbol of Fort Worth as cowboy boots and longhorns, the program in Sundance Square Plaza on Thursday evening should have been a convincer.Eight prominent alumni of the Van Cliburn Piano Competition, including three gold medalists and three silver honorees, gathered to play outdoors in the cold, and a Fort Worth audience came to hear them.The occasion was a commemoration of the first anniversary of the death of Fort Worth’s favorite musical citizen. There was a chill in the air when the program began at 5 p.m., and it was downright shivery by the time it ended some four hours later.The amazing thing was that the pianists played despite the threat of stiff fingers (the four Russian pianists may have considered the air balmy) and gave quite decent performances of a series of piano masterpieces. Their spirit was a strong counter to any idea that musical artists are by nature temperamental.The audience, which filled most of the chairs provided, was attentive. It thinned out some as the evening progressed, but that was almost certainly more due to the temperature than lack of interest in the playing.Most of the eight pianists gave brief spoken tributes to Van Cliburn, crediting him with having a significant impact on their choice of music as a profession. Probably most touching was the tribute of Yakov Kasman, silver medalist in 1997, who spoke his words as if Cliburn were present.The program began with Jose Feghali, gold medalist in 1985, playing The Star-Spangled Banner. He gave a majestic performance whose subtleties in dynamics came across despite some distractions in the surrounding area and the amplification of the sound.(A slight distraction in the early part of the program was that the sound seemed to come from the sides of the plaza rather than the stage. This was corrected later so that pianist and sound came together onstage.)Kasman’s musical contribution was Rachmaninoff’s Sonata No. 2, a work that was completely in the spirit of the Cliburn Competition. The most unusual selection of the evening was one by 1993 gold medalist Simone Pedroni: John Williams’ Suite from the film score for Lincoln. It was a moving and effective choice, beautifully played by Pedroni. Liszt’s Funerailles was a more conventional choice by Pedroni.Stiff fingers were certainly no problem for Steven Lin, who won the jury discretionary award in 2013. He gave a spirited performance of Mendelssohn’s Fantasy in F sharp Minor, one of the highlights of the evening. This was also proof that, despite the solemnity of the occasion, some light-hearted music is not at all out of place.The remainder of the program included a Schumann sonata by Maxim Philippov, silver medalist in 2001; music of Liszt played by Alexey Koltakov, finalist in 2005; pieces by Schumann and Bach played by Feghali, gold medalist in 1985; Liszt and Poulenc by Antonio Pompa-Baldi, silver medalist in 2001; and selections from Tchaikovsky’s The Seasons played by Alexander Kobrin, gold medalist in 2005. Kobrin ended the evening with a performance of Moscow Nights, a signature piece of Cliburn himself.