F-RIS is a hack of "Family Basic V3.0".
In this hack, a background graphic of Saint Basil's Cathedral in Russia was added by Garrett Gilchrist, replacing the Japanese text in the ROM. A cultural monument of Russia, the cathedral commonly appears in versions of Tetris.
No sprites are used, and therefore the playground updates more slowly using the name tables in the background. It's a bit slow at first and may need to be sped up in emulation, but it's otherwise playable.