Binary Barrage Game

Alien invaders march down toward your flak turret, each carrying a string of binary split into groups of three bits. Every group is one digit from 0 to 7, so 101 110 reads as 56. Type the digits and fire to shoot an invader down before it lands. It drills the first step of memorizing binary, turning the bits into digits fast enough that you never have to think about it.

How to play

1. Choose how many bits each invader carries: 3, 6, 9, 12 or 15. That is one to five groups, so one to five digits to type.
2. Read each group of three bits as one digit. 000 is 0, 001 is 1, 010 is 2, 011 is 3, 100 is 4, 101 is 5, 110 is 6 and 111 is 7. The digits 8 and 9 never come up, so the keypad has only 0 to 7.
3. The lowest invader is the target, with its tag lit up. Tap another invader to aim at it instead, or press the left and right arrow keys.
4. Type one digit for each group. It drops into the slot under its group. When every slot is full, press FIRE.
5. One wrong digit misfires. The invader lurches two steps closer, the wrong slots empty while the right ones stay, and the turret jams for 1.5 seconds before it can fire again.
6. An invader that reaches the ground takes one of your four shields. When the last shield falls, the game is over.

Wave 1 sends 6 invaders, and each wave after it sends 2 more. In wave 1 an invader takes 12 seconds to march down with one group, and 3 seconds more for each group after that, up to 24 seconds with five. Each wave's march takes 8% less time than the last, down to half the time of the first. Two invaders are on the field at once in the first waves, and later waves bring up to four.

What you type for an invader stays on it when you aim at another, so you can come back to it. On a keyboard, type 0 to 7, press Enter to fire, Backspace to delete one digit and Delete to clear them all. Escape or Space pauses.

Scoring

• An invader shot down on the first try scores 50 points for each group, plus up to 50 more for each group for how high it still is.
• An invader shot down after a misfire scores 25 for each group.

For example, an invader of three groups shot down at the top of the sky scores close to 300, and one that misfired scores 75.

Your five best scores are saved in this browser for each number of bits, with the wave each game reached. In practice, no shield falls, each key shows the three bits of its digit, and a misfire shows the right digit, so the game goes on until you end it from the pause screen. Practice games are not saved.

Reading binary for memory competitions

Binary is a standard event at memory competitions, with 30 digits to a row. A common method reads three bits at a time as one digit from 0 to 7, so a row is exactly ten digits. Those digits then become images with a number system such as the Major System, so 101 110 is 56, which might be a leash, and the images go into a memory palace.

Beginners lose most of their time on that first step, working out each group of bits. Binary Barrage drills it until it is automatic. When you are ready to memorize real rows, practice with the binary practice tool, and read Binary Number Memorization Systems for more ways to encode binary, including grids of nine bits and the Ben System.

Try our other free memory games, such as Periodic Panic for the periodic table or Echo Invaders for working memory.