Can you be sure to clear a line at Tetris?
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Re: Can you be sure to clear a line at Tetris?
#2Related: in the official specification of the game the pieces ("tetrominoes") are drawn from a bag to prevent the possibility of an unfavorable sequence of pieces that force you to lose the game.
IIRC early implementations of the game did not always behave like that.
https://tetris.fandom.com/wiki/Tetris_Guideline
> You might have heard of the result that you can play forever with bag randomizer, Hold and 3 previews (a similar setup even works with 0 previews). However, the opposite is true, if you play with a randomizer that can generate all piece sequences (e.g. memoryless randomizer). In this article we will present a piece sequence that will top you out - no matter what you do.
https://harddrop.com/wiki/A_deadly_piece_sequence
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.55...
Re: Can you be sure to clear a line at Tetris?
#3This is one of those questions that seems to be wide open for elaborate proofs - but it turns out the total number of possibilities isn't that large, and you can simply enumerate each one.
Re: Can you be sure to clear a line at Tetris?
#4Related: in the official specification of the game the pieces ("tetrominoes") are drawn from a bag to prevent the possibility of an unfavorable sequence of pieces that force you to lose the game. IIRC early implementations of the game did not always behave like that. https://tetris.fandom.com/wiki/Tetris_Guideline > You might have heard of the result that you can play forever with bag randomizer, Hold and 3 previews…
> IIRC early implementations of the game did not always behave like that.
And they were also much better for it, in my opinion (and that of many classic NES Tetris fans).
Re: Can you be sure to clear a line at Tetris?
#5Yes in "Tetris Guidelines". In fact, greater feats can be accomplished in modern Tetris games, thanks to these strong guidelines.
https://www.youtube.com/watch?v=qmG0NcbrLTE
Strong players practice these loops all the time. Its possible thanks to the "bag randomizer".
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The BT Cannon is a TSpin double (4 damage + B2B bonus) + TSpin Triple (6 damage + B2B bonus), for a total of 11 damage.
The DT-cannon followup is a TSpin Triple followed by TSpin Double for a total of 12 damage.
Finally, the Perfect Clear is 10 damage, for a total of 33 damage per loop.
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Other players practice triple-perfect clear starts, for 30-straight damage in some ~30 tetriminos dropped. But the BT-cannon + DT Cannon -> Perfect clear setup is a beautiful arrangement.
The whole loop is carried out over 5 bags IIRC, or 35 pieces (5 bags * 7 pieces per bag == 35 sets of each piece). That's enough for the 4x T-pieces needed for the BT-cannon + DT Cannon (which offer significant amounts of damage)
35 pieces * 4 pieces == 140 minos, or 14 lines (the Tetris board is exactly 10 pieces wide). Which lines up with not only a perfect bag loop (the 35th piece finishes the bag, meaning piece#36 is a new bag, allowing you to loop), but also divides perfectly with 140 minos aka 14 lines, meaning the perfect clear is possible.
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Thanks to Tetris Guidelines bag randomizer, bag#6 is effectively the same situation as bag#1 (start of a new bag). So you loop the sequence and can continuously apply the BT-cannon / DT-cannon / perfect clear loop almost perpetually. In practice, its "only" a 90%+ chance of continuing each loop, but that's a high enough probability to effectively use the technique in competitive games.
EDIT: The existence of the "Hold Piece", in combination with the "easy to count" 7-bag randomizer, allows for some incredible feats in Tetris Guidelines that classic-Tetris players are unfamiliar with. Its a different game, more about quick-reaction speed and twitch reaction rather than the planning-centric classic-Tetris. But its these attributes that make Tetris-Guideline games better for player-vs-player setups. Practiced strategies are more reliable and less contingent on luck.
Re: Can you be sure to clear a line at Tetris?
#6This is one of those questions that seems to be wide open for elaborate proofs - but it turns out the total number of possibilities isn't that large, and you can simply enumerate each one.
Heh, yup. I remember an article on here about some low-level calculation optimization for 32-bit ints that bugged out even with extensive edge-case testing. The conclusion being “just test all the numbers”, 2^32 isn’t that much!
Re: Can you be sure to clear a line at Tetris?
#7This is one of those questions that seems to be wide open for elaborate proofs - but it turns out the total number of possibilities isn't that large, and you can simply enumerate each one.
Heh, yup. I remember an article on here about some low-level calculation optimization for 32-bit ints that bugged out even with extensive edge-case testing. The conclusion being “just test all the numbers”, 2^32 isn’t that much!
Re: Can you be sure to clear a line at Tetris?
#8Is there a good way to reduce SAT or other decision problems to Tetris? Do we need to enlarge the grid to reduce larger problem instances, or can the duration of the play / length of the sequence be used for that?
I would hope for something like "This list of clauses is satisfiable iff there is a winning strategy to clear at least N lines when given the following sequence of tetrominoes". (Where the article here says that there is no hope for anything like this with N=1, but )
Or does knowing the whole sequence in advance make any sequence easy to play / clear any number of lines?
Re: Can you be sure to clear a line at Tetris?
#9There was a kid I knew in school who I would consider a very good tetris player. One time someone else was lamenting that they always get bad pieces and he said, "The Tetris gods will never give you a piece you can't play, you just don't know how to play it." Which has resonated with me for an oddly long time in my life.
Re: Can you be sure to clear a line at Tetris?
#10Is there a good way to reduce SAT or other decision problems to Tetris? Do we need to enlarge the grid to reduce larger problem instances, or can the duration of the play / length of the sequence be used for that? I would hope for something like "This list of clauses is satisfiable iff there is a winning strategy to clear at least N lines when given the following sequence of tetrominoes". (Where the article here says…
In my experience, strong human players can consistently keep track of random-bags and plan out holds, and do so at surprisingly high speeds.
I'm not sure if a computer SAT-solver is needed to accomplish any of the tactics in Tetris-Guidelines.
Maybe it'd be a fun exercise, like using SAT-solvers on human-level Sudoku puzzles. Or for maybe inventing "harder" versions of Tetris, designed for computer players instead of human players.
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I've given some degree of idle thought in how a SAT-solver can maybe discover patterns that would help an intermediate-player develop the eyesight / instincts that strong players have. (Ex: SAT-solver to see the patterns an intermediate player is using, and then analyzing which patterns the player doesn't see yet).
Its a vague / idle thought however, I never seriously attempted to solve the problem. But "training exercises" exist in many video games, and developing tools for human-training / self-training are always useful.
Ex: if a SAT solver could see that the human _COULD_ have performed a King Crimson at some point (https://harddrop.com/wiki/King_Crimson), but the human-player made a mistake and only saw an easier TSpin-Triple setup instead (https://harddrop.com/wiki/T-Spin_Triple).
Such "computer automatic advice" into which elements of your play was possible, and solving it automatically (and determining if it was a good strategy or not) would be very helpful in training.