The pandemic has sidelined many big Beethoven birthday plans. Jonathan Biss was slated to play concerts around the globe in celebration of the 250th anniversary of the composer's birth. Instead, he's home in Philadelphia. So it's no surprise that for this all-Beethoven Tiny Desk concert, Biss chose music that explores the composer's own isolation, brought on by deafness and an uncompromising personality.Biss is uniquely qualified for the task at hand. The 40-year-old pianist has recorded all 32 of Beethoven's freewheeling sonatas, performed them worldwide and has taught an online course in the music.