[Typing]
TetraVex is far from the standout title when you bring up the Best of Entertainment Pack.
Usually it's the heavy hitters, like Chip's Challenge,
JezzBall, SkiFree or even Pipe Dream.
But while edge-matching puzzle games like TetraVex seem dead simple at first,
they become especially interesting when you push the idea further.
There's even a variation that, to this day, has proved unsolvable,
even with the help of computer assistance
and the promise of a $2 million prize.
But before that, let's just talk about plain old TetraVex,
initially released in 1991 as part of the third Microsoft Entertainment Pack
for Windows 3.0.
It's an edge-matching game where you're given a set number of pieces that are all the same shape.
The symbols on each side of each piece must be placed into the grid while matching the symbols
of any pieces adjacent to them.
And at no point can the pieces be rotated.
If you solve the puzzle, you're rewarded with a nice big, yellow smiley face.
Unless you solve the hardest six-by-six puzzle,
and in that case, you get part of the old Microsoft logo known as the "blibbet."
At the minimum, TetraVex puzzles are composed of a two-by-two grid
but as you increase the grid's size, the difficulty increases exponentially.
Considering each piece has at least two possible matches,
and each match has another set of matches,
the complexity of something like a six-by-six TetraVex puzzle is impressive.
Imagine a nine-by-nine puzzle, though,
or God forbid, a 16-by-16.
Six-by-six is bad enough. Forget that.
And I'm not even gonna go into the math, saying just how many possibilities there are with these
because if I did, I'm sure I would lose the interest of most people, myself included, in an instant.
But suffice to say, TetraVex and edge-matching puzzle games are deceptively challenging
once you go past a certain grid size.
Of course, I say "challenging" in referring to human players, though,
because for a computer, even a 16-by-16 grid is a piece of cake to figure out
since it's just straight-up number crunching.
So, what about the variant I mentioned earlier that has never been solved, even by computers?
Well, say hello to the Eternity II puzzle,
designed by Christopher Walter Monckton
and sold by Tomy UK, Ltd.
It works using the same basic idea as TetraVex and other edge-matching puzzle games,
but the changes made are downright devious.
There are 256 pieces in a 16-by-16 grid,
each of which can be rotated
with a starter piece which must be placed in the center of the board.
Among these pieces, you'll find a total of 22 colors, plus the gray edges,
with five of these colors only found on border and corner pieces
and the other 17 colors appearing only on inner pieces and the sides of the borders.
This design ensures that computers have an insanely hard time figuring it out
and it was made this way specifically because the first Eternity puzzle
was able to be solved by using a brute-force computer program,
one which netted Alex Selby and Oliver Riordan a one million pound reward.
So, Mr. Monckton collaborated with these two when creating the next iteration.
using a similar algorithm to create a puzzle so ridiculous
that by their estimation, if you used the world's most powerful computer,
and let it run from now until the projected end of the universe,
it would probably still not even find *one* of the nearly 20,000 possible solutions.
This is because the projected number of solutions,
taking into account the configuration of the board and its multicolored pieces,
comes to a staggering 3.11 x 10 to the 545th power.
So, knowing this, they were pretty confident in the thing
and the $2 million prize was offered to anyone that could provide even one complete solution
by the end of 2010.
It was never claimed and the puzzle remains unsolved.
A consolation prize of $10,000 was rewarded to Louis Verhaard
for a partial solution with 467 matching edges out of 480 in 2008.
But it's estimated that for the final 13 edges to be solved any time soon,
an algorithm several orders of magnitude more efficient would be required.
In short, edge-matching puzzle games are no joke,
with Eternity II pushing the limits to absurd levels.
So next time you play a game of TetraVex,
why not take a step back and admire how simple it appears,
while still presenting a taxing mental challenge.
And perhaps breathe a sigh of relief that even with a six-by-six grid,
it's nowhere near as inhumanly difficult as it could be.
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but some, you know, stuff like floppy disks that I've signed and-- you know, whatever.
Not quite on the same level, but either way,
thank you very much for watching.