Tetris

Goal: Rotate and arrange falling blocks (called tetrominoes) so they form complete horizontal lines. A completed line disappears, freeing space for more pieces. The game speeds up and ends if the stack reaches the top.

The Playfield

Tetris is played inside a vertical well that is 10 cells wide and 20 cells tall. Pieces fall from the top; you must guide each one to a stable landing spot before the next piece appears.

The Seven Tetrominoes

Every piece is made of exactly four square cells. The seven shapes are named after the letter they most resemble:

• I – A straight four-cell line. The only piece that can clear four lines at once (a "Tetris").
• O – A 2×2 square. It does not rotate; treat it as a fixed block.
• T – A T-shape. Versatile and central to many advanced techniques such as the T-spin.
• S – An S-shape that zig-zags right when flat.
• Z – A Z-shape that zig-zags left when flat.
• L – An L-shape with the foot pointing right when upright.
• J – A J-shape with the foot pointing left when upright.

Pieces appear in a randomized sequence (Modern Tetris uses the "7-bag" system, which guarantees each of the seven pieces appears once before any repeats).

Controls

• Left Arrow / Right Arrow – Move the falling piece one cell horizontally
• Up Arrow – Rotate the piece 90° clockwise
• Down Arrow – Soft drop – accelerates the fall while you hold the key (small bonus per cell)
• Space – Hard drop – instantly slams the piece to the lowest possible position (large bonus per cell)

Line Clearing & Scoring

When a row is completely filled, it vanishes and every block above it drops by one row. Clearing multiple lines simultaneously earns progressively more points:

• Single (1 line) – 100 points
• Double (2 lines) – 300 points
• Triple (3 lines) – 500 points
• Tetris (4 lines) – 800 points

Soft drops and hard drops also add small bonuses based on how many cells the piece descended.

Game Over

If a new piece spawns and cannot fit on the playfield because the stack has reached the top, the game ends. The higher the stack, the closer you are to losing — keep the field as flat as possible.

Classic vs Challenge Mode

Classic Mode – Start from an empty board. The drop speed gradually increases as you clear more lines.

Challenge Mode – The board starts partially filled with garbage blocks. You must clear the existing mess while managing new falling pieces — perfect for testing sustained tactical skill under pressure.

Keep the Field Flat:

• Minimize height differences across columns. A flat stack gives every piece a useful home and avoids forced placements.
• Tall peaks create dead space — if one column is much taller than its neighbors, you'll struggle to slot I, S, and Z pieces safely.
• Whenever a piece can land flat instead of creating an overhang, prefer the flat landing.

Save a Column for the I-Piece (Build for Tetrises):

• Leave the far-left or far-right column empty while filling the rest of the board. When an I-piece arrives, drop it vertically into the gap to clear four lines at once for the maximum 800-point bonus.
• A stack that's 9 columns wide and 4 rows tall, plus an empty column, is the canonical Tetris setup.
• Be patient — don't waste I-pieces on singles or doubles if your stack is already built for a Tetris.

Plan Rotations, Not Just Positions:

• Visualize each piece in all four rotations before placing it. A poor rotation locks the piece into a bad spot.
• For S and Z pieces, remember they only fit cleanly in two of four orientations — placing them flat against a step is usually safest.
• For L and J pieces, the foot can hang over an edge to fill a one-cell gap below.

Soft Drop vs Hard Drop:

• Soft drop for delicate placements — it lets you slide the piece along the floor ("floor kick") for last-second adjustments.
• Hard drop for confident placements — it locks instantly, saving precious seconds at high speed.
• At slow speeds, prefer soft drops to keep control; at fast speeds, mix in hard drops to keep up with the pace.

Use the Next Preview:

• Always glance at the Next piece before committing the current one. Plan two moves ahead: "Where does this piece go, and where will the next one go after it?"
• Knowing whether an I-piece is coming lets you leave the Tetris column open; knowing a flat O is coming lets you fill a 2×2 hole.

Advanced Techniques:

• T-Spin – Rotate a T-piece into a tight slot that it couldn't reach by sliding alone. T-Spins reward bonus points in modern Tetris and are essential in competitive play.
• S/Z Stacking – Build a serrated staircase with S and Z pieces to set up clean, repeated line clears without flattening the entire field.
• Perfect Clear – Plan a placement that empties the entire field at once. Extremely difficult, but worth a massive score bonus in many implementations.
• Downstacking – When you have garbage rising from below, dig vertically to expose and clear the holes before adding new pieces on top.

Survival Habits:

• At very high speeds, focus on not topping out rather than maximizing score. A safe flat placement beats a clever Tetris that costs you the game.
• Keep at least one column shorter than the others — it gives you a safety valve when an awkward piece arrives.

Tetris is one of the most iconic and influential video games ever made. It was created in June 1984 by Alexey Pajitnov, a Russian computer engineer working at the Dorodnitsyn Computing Centre of the Soviet Academy of Sciences in Moscow. Pajitnov originally built it on an Elektronika 60 terminal as a test of his programming skills.

Origin of the Name: The word "Tetris" combines "tetromino" (a shape made of four squares) with "tennis" — Pajitnov's favorite sport. The result is one of the most recognizable names in gaming history.

Path to Global Fame: For years Tetris spread informally through floppy-disk trading behind the Iron Curtain. Its commercial breakthrough came in 1989 when Nintendo bundled a portable version with the Game Boy in North America and Europe. That single decision turned Tetris into a household name — the Game Boy version alone sold more than 35 million copies and introduced puzzle gaming to an entire generation.

Cultural Impact: Tetris has appeared on more than 50 platforms, from arcades and consoles to calculators and oscilloscopes. It has been the subject of academic research, films (the 2023 biopic Tetris), and even a 1990s Soviet-era licensing dispute that became one of the most famous business stories in gaming. Researchers have documented the "Tetris Effect" — a phenomenon where players see falling blocks in their mind's eye after extended play.

Cognitive Benefits: Tetris is one of the most-studied video games in psychology. Notable findings include:

• Spatial reasoning – Players get faster at mentally rotating objects, a skill that transfers to other tasks.
• Reaction time – Sustained play improves split-second decision-making.
• Stress and trauma – Studies at Oxford and elsewhere suggest playing Tetris shortly after a traumatic event may reduce intrusive memories.
• Flow and focus – The simple but demanding loop reliably produces a flow state, making it a popular short mental reset.

This Implementation Includes:

• ✅ Both Classic and Challenge modes
• ✅ Authentic 10×20 playfield with the seven standard tetrominoes
• ✅ Smooth keyboard controls (move, rotate, soft drop, hard drop)
• ✅ Next-piece preview so you can plan ahead
• ✅ Standard line-clear scoring (100 / 300 / 500 / 800) plus drop bonuses
• ✅ Persistent score tracking across sessions

Note: Tetris is for entertainment and light cognitive exercise. Tetris is a registered trademark of The Tetris Company; this is an educational implementation that does not claim affiliation.