Maarten Regtien currently is working on the four part Piano Concerto No. 4 (Emperor Penguin) (2023-2024).
Part 1 already is finished (juli 2023) and is available for listening on various platforms like Spotify and YouTube.
The score of Part 1 is in the final stage of correcting the layout; it will be published as soon as possible, also as a read-along video.
Part 2 will be based upon a ragtime Regtien wrote when he was about 12 years. Writing is in progress...