Spectra

Spectra hides one colour a day and compresses it into three digits. Red, green and blue each run from 0 to 9 rather than 0 to 255, so the whole answer is something like 7-4-5, and you have six goes to name it. The mystery swatch is not shown while you play, only a dark tile with a question mark, which kills any temptation to eyeball it.

1. Set each channel with the ▲ and ▼ steppers under R, G and B. Everything starts at 5, dead centre.
2. Press GUESS. Your triple drops onto the board as a row of three digits, and the strip beside it fills in with the actual colour those digits make, so you build a visual record of where you have been.

Colour games usually reward people with good eyes. Spectra deliberately does the opposite: it hides the answer swatch entirely and hands you a pure logic problem wearing colour as a costume, and the page says as much when it insists this is not eyeballing. Because the search space is exactly a thousand triples and the feedback splits it three ways per channel, a careful player really can bracket it in three or four rows, which gives every guess a satisfying feeling of arithmetic rather than luck. It also loads instantly with no account, no ads and nothing tracking you, which is rarer than it should be.

The colour code does two jobs at once, which is what makes the deduction tight. Green, yellow and grey give you distance; the arrow gives you direction. Opening on 3-3-3 and getting grey-up, yellow-up, yellow-up puts red at 6 or more while green and blue are pinned to 4 or 5, and that single row cuts the thousand possible colours down to sixteen. Two rows later the board is solved. The banner then flips to read the RGB triple and the board reports "Solved in 3/6", with a share button that produces a spoiler-free emoji grid.

Daily colour

The numbered puzzle everyone gets, six guesses, reset at midnight UTC.

Play Unlimited

Offered on the results card once the daily is done, for people who want to keep going without waiting for tomorrow.

• Open at 3-3-3 or 6-6-6 rather than the default 5-5-5. Dead centre wastes the arrows, because a yellow at 5 leaves you two live values on each side, whereas an off-centre opener converts every arrow into a much narrower band.
• Grey is more useful than it looks. It does not just mean wrong, it guarantees a gap of at least three, so a grey-with-up-arrow on a 3 immediately deletes everything from 0 to 5 in that channel.
• Solve channels independently. There is no interaction between red, green and blue here, so treat the board as three separate number-guessing games running in parallel and spend each guess on whichever channel is still widest.