TETRAS, the shortest Tetris and one of the oldest (November 1990!)
Author: Somebody at HP?

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³ Mini-instructions: Type speed number (0 to 32?) and press TETRAS.  -jkh- ³
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Joe Ervin writes:

> There are already at least 3 or 4 versions of Tetris already for the HP48. 
> Some of which are done in pure machine language and run very nicely.
> I can think of nothing less exciting than another Tetris.

So you are thinking, "For crying out loud, not ANOTHER Tetris?!?  Why?!?"

For purely historical reasons.  This one might be from HP!  As evidence, here
are some excerpts from the original posting (author's name withheld):

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Date: Sat Nov 10 1990

Ok.. I have TETRAS from a friend who says that its roots can be traced
back to HP...  It is in M-L and it is very fast... (obviously)... at its
highest setting, there is little more than a blue streak on the
screen... it is very small too, only 1880 bytes!

BTW, it _is_ spelled TETRAS -- aparently the person who wrote it wanted
it that way.
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[To run, first type a speed (0 thru 32) then press TETRAS.  The control keys
 are listed on the display.  Note: If you exit early by pressing ON, a list
 will be left on the stack, containing the current game status.  To continue
 the game, run TETRAS with that list in level one.  -jkh-]