\myheading{Origins of Tetris: a hypothesis}

I don't know how Alexey Pajitnov invented Tetris, but here is my hypothesis.

There is a class of bin packing problems, see 
\ref{backups},
\ref{VM_packing},
\ref{tiling}.

And pentomino figurines were quite popular as tests for packing problems,
see the work of Solomon W. Golomb\footnote{\url{https://en.wikipedia.org/wiki/Polyominoes:_Puzzles,_Patterns,_Problems,_and_Packings}}.

Another variation of bin packing problem is \emph{online bin packing} -- an algorithm is blind to the whole
input, it only sees the current figurine and maybe the next one.
But it have to pack all figurines to some box.
\emph{Online} in computer science means that an algorithm must work while observing only a small part of input.
Almost like UNIX pipes...

\begin{framed}
\begin{quotation}
A good example is large-scale parcel packag-ing in modern logistics systems (Figure. 1), where parcels are mostly in regular cuboid shapes, and we would like to collectively pack them into rectangular bins of the standard dimension. Maximizing the storage use of bins effectively reduces the cost of inventorying, wrapping, transportation, and warehousing.
\end{quotation}
\end{framed}
( \url{https://arxiv.org/pdf/2006.14978.pdf} )

And this is what Tetris players do all the time: they serve as a robot who take objects/figurines from a conveyor belt and pack them
into boxes.
A player sees only current object, and maybe a next one.

A player may think that figurines are dropping from the top, but take another look on it: figurines may be moving on conveyor belt
from top to down.
And not dropping at all, just moving slowly.

And how does the game reward you?
When your packing is tight, with no voids (filled rows disappears).

This is what I observe almost daily in my real life near a house where I rent my flat:
a backyard of an office of a highly popular Ukrainian delivery company ``Nova Poshta''\footnote{``New Post''},
a guy in a company's uniform packs all sorts of boxes into a van, when these boxes are coming from a hatch in a wall.

Pajitnov worked for \emph{Dorodnitsyn Computing Centre of the Soviet Academy of Sciences} -- not a videogame company.
Probably he was busy with such an algorithm?

You may notice that virtually all puzzle games for smartphones that are popular now, are actually NP-problems.
Someone can go even further:
A human-based computation game or game with a purpose\footnote{\url{https://en.wikipedia.org/wiki/Human-based_computation_game}}.