A modern take on Matthias Wandel's classic [0], which has you guess a variety of geometric attributes (e.g. angle bisection, centroid locating, shape regularization), not just simple partitioning of a line.

[0] https://woodgears.ca/eyeball/index.html

This is great. If only the little square tool would disappear while I make adjustments though - it's just enough of a distraction to barely miss.

Oh wow - that is very cool. Thanks for sharing.

https://eyeball.rory.codes/ I was 0.20% off on eyeball. Beat me: https://eyeball.rory.codes

The fact that the numbers are in a brighter color than the end marks, and that the numbers go inwards, makes it slightly more difficult than it would otherwise be, because the eye is biased by the more prominent space between the numbers being different from the line between the marks.

Love it!

It would be great to have a 'training' mode, where you get to repeat ones you miss. This would increase the learning speed.

Easy training- repeat the one you just borked Medium training- cycles through say 5 examples until you get all five within your target range (1%, 0.1%, whatever)

Cool idea - thanks! I'm building a mobile app as we speak so I'll add it for sure.

I was 0.06% off on eyeball. Beat me: https://eyeball.rory.codes.

This is fun!

0.10%, but on a touch screen.

> perfect - you picked 0 · off by 1 (0.03%)

Almost: 0.07%, allegedly 'perfect'. Getting an early win makes the game so much more 'playable'.

Why does an early win matter? Isn't it random?

Great idea! Have you considered storing triplets <range, correct number, selected number> for each try and making image plots of these (x/y coordinates are correct/selected numbers, color of each pixel represents frequency) for multiple users for each range? I think the image might reveal interesting properties of human eyeballing, like near-perfect accuracy around 50%, but with less obvious correlations.

Very cool idea! Will try and add.

Really fun! I am pretty much blind

0.11% by luck, because I actually got lucky the target number was too close to zero, out of a big scale.

I love these kind ones! Really engaging also yes as someone commented, the training mode would be an awesome idea.

Also, I tried this on laptop as well as my phone, I liked it more on my phone (I know the whole point is about precision though)

I'm* building an app currently!

*my old pal Claude

Cool idea, love how simple it is. Minimal and clean.

Oh, this is actually fun! How about if you change the target every few seconds to add a bit of pressure.

Definitely need an iOS version! An angle version on a circle would be nice too.

What does native give you that this doesn't?

Just wrapping up the beta for iOS! Will let you know asap.

Simple premise, oddly hard to put down.

This is fun but you need to put "click the line" higher on the page. It took me a while to figure out what I was looking at.

Just any kind of contrast between foreground and background would help.

same happened to myself as well.

10 round avg 4.5%.

A time limit would make sense imho. For extra challenge, add diagonal or curved lines.

800

0 out of 1,600

I still missed. Even when there was centered text.

Maybe the human is the weakest link

pretty fun!

this is fun and helping me get grounded :). adding a timer would be a good idea, I think.

10 perfect hits in a row!

...

handleClick({clientX: els.bar.getBoundingClientRect().left + els.bar.getBoundingClientRect().width / state.n * state.target })

this was fun

this is fun!

my avg was around 2% not able to do more than that lol

i made 0.87%

my best is 0.08%

> I was 0.00% off on eyeball. Beat me: https://eyeball.rory.codes

(It was pure luck)