# Solution to Pentris

### by Reid Barton

The first time you try to play this Tetris-like game, you will
probably lose fairly quickly. When you do so, a "high scores" list
will pop up showing Mr. E. Hunt with a score of 89999. Your goal,
then, is to score 90000 points.

A little experimentation will reveal that you score points as a
result of forming lines, and the more simultaneous lines formed, the
bigger the score bonus; you get 1 point for forming a single line, 10
points for forming two lines simultaneously, 100 points for three
lines, 1000 points for four lines, and finally 10000 points for
forming five lines at once, by dropping in a piece which is a column
five squares tall.

It turns out that the game gives you a fixed sequence of 90 pieces,
and every tenth piece (and no others) are five-square-tall columns.
So, the only way to score 90000 points is to assemble each of the nine
sets of ten pieces into the bottom five rows of the Pentris well, with
the tenth, vertical piece clearing all five rows. There is a unique
way to do this with each set of ten pieces.

Some of the pieces are marked with one of three symbols. The image
to the right of the applet can be overlaid exactly on the applet
frame, with the grid of letters lying over the Pentris well. When the
pieces of each subpuzzle are assembled correctly, the marked squares
on the pieces correspond to letters in the grid which, when read in
order of the subpuzzles (multiple marked squares in a single subpuzzle
being read in the order that the types of marks first appear in the
puzzle), spell out the answer, **ATLANTICSALMON**.

The solutions to the individual subpuzzles are below.

*2006 MIT Mystery Hunt*