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Knumber Knower
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About the game
Knumber Knower is a quick test of reading numbers at a glance. The screen shows two numbers, one above the other, and you have to say whether the top one is greater than, equal to or smaller than the bottom one before the time runs out.
The catch is the typeface. Normally every digit takes up the same width, so numbers line up and longer ones look longer. Here each digit has a width of its own, which makes a narrow number with more digits look shorter than a wide one with fewer. Your eyes will try to fool you.
Each correct answer adds a point. The numbers start with two digits and grow by one digit every ten points, up to six. One wrong answer, or one late answer, ends the run and shows your score.
Playing it here
This is a CHIP-8 program. CHIP-8 is a small virtual machine from 1977, created for hobby computers like the COSMAC VIP, and people still write new games for it today. Knumber Knower uses only the original CHIP-8 instructions and fits in under 3.5 KB, so it would run on a real COSMAC VIP. It was made for Octojam 10, a yearly CHIP-8 game jam, and runs here in the Octo emulator.
Click Play and press W to get past the title; the first time, a screen with the controls follows. The arrow keys work in place of A, W and D. F2 saves the state of the emulator at any moment and F4 brings it back. A gamepad works too, with the D-pad: left, up and right.
Controls
| Key | Action |
|---|---|
| W or up arrow | advance through the title and the instructions; answer "equal" |
| A or left arrow | the top number is greater |
| D or right arrow | the top number is smaller |
| any key | leave the score screen |
| F2 / F4 | save / load the state |
A few things worth knowing
Watch the dot. A single dot moves from right to left along the bottom of the screen. When it reaches the left edge, about a second and a half later, the round is lost.
Count digits before you compare. With numbers of different lengths, the one with more digits is bigger, however short it looks. Only when the lengths match do you need to read them from the left.
The three marks follow the keys. The symbols across the middle of the screen sit in the same order as A, W and D on the keyboard: left for greater, middle for equal, right for smaller.
Credits and licence
Knumber Knower was created by John Earnest, who also wrote the Octo toolchain and emulator and maintains the Chip8 Community Archive. The game is in the public domain under CC0 1.0, like everything in that archive, and the Octo emulator is released under the MIT licence. The licence text is linked from this page.