How do you play Blocks?

Pieces of four blocks fall from the top of a ten by twenty playfield. Move and rotate them so they land without gaps, then clear complete rows. Each cleared row pushes the stack down and awards points, and the game ends when a new piece cannot enter the board.

What does the outline below the falling piece mean?

It is a ghost piece: an outline showing exactly where the current piece will land if you drop it without moving sideways. It removes the guesswork from timing a drop.

What is a seven-bag randomiser?

Instead of picking each piece independently at random, the game shuffles one of each of seven shapes into a bag and deals them out. Every piece therefore appears exactly once every seven draws, so you can never go long stretches without an I-piece.

How does scoring work?

Clearing one, two, three or four rows at once scores 100, 300, 500 or 800 points multiplied by the current level. Soft dropping adds one point per cell descended. The level rises by one for every ten rows cleared, and pieces fall faster at each level.

Play Blocks — Free Falling Tetromino Puzzle Game Online

The rules

Seven piece types fall one at a time into a well ten columns wide and twenty rows tall. Each piece is made of four blocks. You can shift a piece left and right and rotate it, but you cannot stop it: it descends continuously, faster at higher levels, until it lands on the floor or on the stack.

When a row becomes completely filled it clears, everything above it drops one row, and you score. When four rows go at once the reward is disproportionately large, which is the whole strategic tension of the game: build a flat, well-ordered stack and clear high, rather than chasing single rows and burying yourself in holes.

Controls

← → or A D	Move the piece sideways (holding repeats)
Z	Rotate clockwise, with wall kicks
X	Rotate anticlockwise
↓	Drop faster, one point per cell
Space	Start, or restart after a game over

Reading the board

The hollow outline under the falling piece is a ghost piece. It shows exactly where the piece will come to rest without any sideways input, which makes it possible to judge a drop precisely instead of guessing. The ghost is drawn as an outline rather than a filled shape so it never gets mistaken for the piece in play.

Notes on the implementation

Each of the seven shapes is stored as four rotation states, so rotation never needs matrix maths at runtime and never produces a malformed piece. Rotating against a wall would normally fail, so rotation tries a short list of horizontal kick offsets before giving up — that is what lets you turn a piece while flush against the edge, an interaction that looks trivial and is not.

Pieces are dealt from a seven-bag: one of each shape is shuffled and dealt, then the bag is refilled. Every piece appears exactly once per seven draws, so a run cannot be destroyed by a twenty-piece drought of the only shape that fits the gap you left. Horizontal movement uses a short repeat delay, so a tap is one cell and a held key slides.

Genre	Falling-block puzzle
Playfield	10 × 20 cells
Pieces	7 tetrominoes, four rotations each
Randomiser	Seven-bag
Scoring	100 / 300 / 500 / 800 × level
Ends when	A new piece cannot fit