The level increases with every 20 lines completed and is increasingly faster 
and more difficult. My record  is something like 13.000.

The HP 50g is the latest calculator in the 49/50 series, introduced in 2006. 

This program works with an HP50g or HP49G+. You can run it directly from the 
SD card (press EVAL) or store it in memory:  
tetris.cod 
'Tetris' STO

https://www.youtube.com/watch?v=K_6BI5PvKkE

