But some piano roll artists made a name with pieces that couldn't possibly be played by an actual person. From around 1950 on, we have the works of Conlon Nancarrow, who found that most pianists of his day could not meet the demands of his complicated pieces, so he turned to write music specifically for the player piano. Most of his studies deal with complicated meters and polyrhythms. Many contain distinct voices playing the same line at different tempos, often in odd ratios. On top of this, most of the lines themselves tend to be highly dissonant and hard to actually play. While some of his earlier studies were influenced by jazz - some of them are quite catchy - the later ones are basically just random, and don't really sound like much as a whole.