:A sideways Tetris variant : HecaTris
Download (Version 1.0.1) HecaTris.ZIP (for Psion Series 5 and 5mx).
Download (Version 1.3.0) HecaTris130.ZIP (for Psion Series 5mx Pro and Psion netBook).
Decompress it, and put the resulting files in the \System\Apps\HecaTris directory on your Psion.
