Falling Blocks — rotate, fit, clear the line

Seven four-square pieces fall one at a time, and any row you fill across all ten columns disappears. It is the falling-block line-clear genre often called tetris-style, implemented here to run entirely in your browser. Pieces arrive one shuffled set of seven at a time, so no shape goes missing for long, and rotation nudges the piece a square or two when a wall is in the way. Your best score is kept in this browser, and nothing is installed.

How to use

  1. Move the piece with the on-screen arrows or the left and right keys. On a phone, drag across the board and the piece follows your finger.
  2. Rotate with ↺ / ↻ or the up arrow. If a wall or the stack blocks the turn, the piece is nudged a square or two and the rotation still lands.
  3. Press ▼ to drop one row, or ⤓ / space to slam it to the floor. Both award points for the rows crossed.
  4. Use ⇄ to park the current piece in the hold slot and take it back later — once per piece.

A row vanishes the moment all ten of its cells are filled, and everything above slides down one row. Clearing several rows in one drop is worth far more than clearing them one at a time.

Every ten cleared rows raise the level by one, and each level makes the pieces fall faster. The interval stops shrinking at 0.08 seconds.

A piece does not lock the instant it touches down: you get half a second, and moving or rotating restarts that clock, which is what makes last-moment slides possible.

The best score lives in this browser (localStorage) and is never sent to a server.

In depth

The rules: seven shapes, ten columns

The board is ten columns wide and twenty rows tall. Four-square pieces fall from the top, and when a row is filled across all ten columns it disappears and everything above drops by one. The seven shapes are named I, O, T, S, Z, J and L after what they look like.

This is the genre usually described as tetris-style. What you are playing is an independent implementation of those mechanics — seven pieces, a ten-wide well, line clears and rotation kicks — rather than any particular commercial version.

The tension in the game sits between the square that is convenient now and the shape you will need later. Dropping pieces wherever they fit leaves a jagged surface, and a jagged surface accepts almost nothing except the I piece. Skill in this game shows up in surface management long before it shows up in reflexes.

Wall kicks: why a piece against the wall still turns

When a piece is flush against a wall or the stack, the rotated shape often does not fit where it stands. Instead of refusing the rotation, the game tries a short list of nearby offsets and uses the first one that fits. Those offsets are the wall kicks.

This page uses the offset tables that became the de facto standard for the genre: five candidate positions per rotation, tried in order. The I piece has its own table, because a four-long bar sharing the other table would be nearly unrotatable beside a wall.

Kicks are what make standing a piece up against the wall, and twisting one into a gap, part of normal play. Without them a vertical I hugging the right wall can never lie down, and the board ends with one unfillable column.

Scoring: why four rows at once is worth double

Points depend on how many rows a single placement clears: 100, 300, 500 and 800, multiplied by the level. Four separate single clears pay 400; the same four rows taken together pay 800. The bonus for waiting is exactly a factor of two.

That curve is the strategy. While you hold three filled rows waiting for the fourth, the stack keeps rising, and the doubled payout is what you are paid for carrying that risk. Remove the bonus and the game collapses into tidy housekeeping with no decision in it.

Dropping is worth points too: two per row on a hard drop, one per row on a soft drop. The amounts are small on purpose — enough to reward decisive play without making speed the whole score.

The level multiplier climbs every ten cleared rows, so a four-row clear late in a game outweighs several early ones. Surviving is itself a scoring strategy.

Stacking well: keep the surface flat

The habit that matters most is keeping the top of the stack flat. Height differences shrink the set of pieces that fit, and a one-column-deep notch can only be filled by an I. Before you place a piece, look at the shape it leaves behind rather than the row it completes.

Leaving one column empty on purpose — the well — is the classic way to chase the four-row bonus: fill nine columns across four rows, then drop an I down the gap. Because pieces come in bags of seven, an I is never more than twelve pieces away, but you still need enough headroom to wait.

Never bury a hole. A gap under a locked block cannot clear until everything above it is removed, and a single buried hole usually costs the rest of the game. Most beginner losses trace back to one hurried placement rather than to speed.

Treat hold as savings rather than as a bin for awkward pieces. If you are digging a well, park an I there and wait until three rows are ready.

As the level climbs, decide early. Read the next piece while the current one is still falling and you will keep up with speeds that look impossible when you decide late.

Speed and how a game ends

At level 1 a piece takes 0.8 seconds to fall one row, and every level shaves 0.07 seconds off that. The interval floors at 0.08 seconds because anything faster crosses human reaction time and turns the outcome into luck.

Touching down is not the same as locking. You get half a second of lock delay, and moving or rotating restarts it. That window is what makes the genre's signature last-instant slide into a gap possible.

The game ends when a new piece has nowhere to spawn, which is also what the two hidden rows above the visible board detect. That is why a game can end while the visible board still looks survivable.

How this page is built

Pieces are dealt from a shuffled bag of all seven shapes. With uniform random draws you get runs of six identical pieces and droughts of thirty without an I, and a loss inside a drought says nothing about how you played.

The four rotation states of each shape are generated by rotating the base grid rather than typed out by hand. Hand-written rotation tables are where this genre's most common bug lives: one cell out of place in one state, invisible until a specific wall kick.

The board is twenty-two rows tall and the top two are hidden. They are where pieces spawn and they double as the game-over sensor: a locked block reaching them ends the game.

Gravity runs on a single 50-millisecond timer that accumulates time and applies the level's interval. Re-creating the timer whenever the level changes would silently drop one step of gravity at exactly the moment the game speeds up.

The best score stays in this browser. Nothing is uploaded, so there is no global leaderboard — and clearing site data clears the record.

FAQ

In what order do the pieces arrive?

All seven shapes are shuffled into a bag and dealt in that order, then a new bag is shuffled. The same shape can appear twice in a row across a bag boundary, but you will never wait thirty pieces for an I. Pure random selection produces those droughts, and losing to one is not a skill outcome.

How often can I use hold?

Once per piece. The first hold takes the next piece from the queue; after that it swaps the falling piece with the stored one. Unlimited holds would let you swap two shapes forever and stall the game, so the lock resets only when a piece is placed.

How is the score calculated?

By rows cleared in a single drop: 100, 300, 500 and 800, multiplied by the current level. A hard drop adds two points per row crossed and a soft drop one. Four rows at once pays 800 where four separate singles pay 400 — exactly double for the patience.

When does the game end?

When a new piece has no room to appear, or when locked blocks reach the two hidden rows above the visible board. The board does not have to look full; it only has to be full where the next piece would spawn.

Does it work on a phone?

Yes. The on-screen pad covers every action, and on the board itself a horizontal swipe moves the piece, a downward flick hard-drops it and a tap rotates. Nothing is installed and it keeps working offline.

Method and sources

What this tool bases its numbers on, and how far those numbers go.

What this tool is
This is an independent browser implementation of a falling-block line-clear game. It is not an official version of any branded product, and the scoring and level rules are the ones this page defines.
Formula
The well is 10 columns by 22 rows with the top 2 hidden. Seven shapes are dealt from shuffled bags. Line scores are 100, 300, 500 and 800 multiplied by the level; the level rises every 10 cleared rows. Gravity starts at 800 ms per row, drops 70 ms per level and stops at 80 ms.
Worked example
Clearing four rows at level 3 scores 800 × 3 = 2,400. Clearing those same four rows one at a time scores 100 × 3 × 4 = 1,200.
Limitations
  • Draw luck can end a game you were playing well. Bag randomisation limits droughts; it does not remove them.
  • The best score is stored in this browser only. Clear site data or open the page elsewhere and you start from zero.
  • Piece order comes from Math.random, so there is no seed to share and no way to replay a board.
  • The kick tables follow the offsets in common use for this genre, but they are not guaranteed to match any specific commercial version cell for cell.
  • Advanced scoring rules such as twist bonuses are not implemented. Points depend only on rows cleared and the current level.
Effective date
Last reviewed

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