BNPS.co.uk (01202) 558833.Picture: Bjorn Perborg/BNPS.co.uk..Chopin half! This grand piano could be the narrowest in the world but pianists won't have the chance to play a waltz or a sonata - as it has just five keys. With notes in C, C sharp, D, D sharp and E, composers would struggle to come up with a classic for this instrument. The 3.5ft tall organ was created by sculptor Bjorn Perborg, who took a saw to a grand piano that was being thrown away. He recently sold the piano at an exhibition for £2,400 to a museum.