Query: What instrument did Chopin play for Charles Hallé when the latter visited him?
Context: He was forced by illness to decline a written invitation from Alkan to participate in a repeat performance of the Beethoven Seventh Symphony arrangement at Erard's on 1 March 1843. Late in 1844, Charles Hallé visited Chopin and found him "hardly able to move, bent like a half-opened penknife and evidently in great pain", although his spirits returned when he started to play the piano for his visitor. Chopin's health continued to deteriorate, particularly from this time onwards.