Show HN: Eyeball(eyeball.rory.codes)
141 pointsby mrroryflintJun 2, 2026

32 Comments

nextmaJun 2, 2026
my best is 0.08%
zer0toninJun 2, 2026
> I was 0.00% off on eyeball. Beat me: https://eyeball.rory.codes

(It was pure luck)

trickybusinessJun 2, 2026
this is fun!
zer0toninJun 2, 2026
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.
ketul_shahJun 2, 2026
same happened to myself as well.
oneeyedpigeonJun 2, 2026
Just any kind of contrast between foreground and background would help.
elliotJames548Jun 2, 2026
i made 0.87%
ketul_shahJun 2, 2026
this is fun and helping me get grounded :). adding a timer would be a good idea, I think.
pedromlsreisJun 2, 2026
0.11% by luck, because I actually got lucky the target number was too close to zero, out of a big scale.
forlorn_mammothJun 2, 2026
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)

mrroryflintJun 2, 2026
Cool idea - thanks! I'm building a mobile app as we speak so I'll add it for sure.
ashm1104Jun 2, 2026
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)

mrroryflintJun 2, 2026
I'm* building an app currently!

*my old pal Claude

ramon156Jun 2, 2026
800

0 out of 1,600

I still missed. Even when there was centered text.

Maybe the human is the weakest link

zokierJun 2, 2026
10 round avg 4.5%.

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

davidcollantesJun 2, 2026
I was 0.06% off on eyeball. Beat me: https://eyeball.rory.codes.

This is fun!

TheodoresJun 2, 2026
Almost: 0.07%, allegedly 'perfect'. Getting an early win makes the game so much more 'playable'.
stavrosJun 2, 2026
Why does an early win matter? Isn't it random?
pelagicAustralJun 2, 2026
> perfect - you picked 0 · off by 1 (0.03%)
layer8Jun 2, 2026
0.10%, but on a touch screen.
tgammaJun 2, 2026
I was 0.00% off on eyeball. Beat me: https://eyeball.rory.codes

Lucky punch, on a touch screen!

0x000xca0xfeJun 2, 2026
10 perfect hits in a row!

...

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

joey9printsJun 2, 2026
Cool idea, love how simple it is. Minimal and clean.
aspectopJun 2, 2026
my avg was around 2% not able to do more than that lol
antoine-codeflyJun 2, 2026
Definitely need an iOS version! An angle version on a circle would be nice too.
mrroryflintJun 2, 2026
Just wrapping up the beta for iOS! Will let you know asap.
tantalorJun 2, 2026
What does native give you that this doesn't?
throwawaydudhdnJun 2, 2026
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.
mrroryflintJun 2, 2026
Very cool idea! Will try and add.
tt_devJun 2, 2026
this was fun
MontyCarloHallJun 2, 2026
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

mrroryflintJun 2, 2026
Oh wow - that is very cool. Thanks for sharing.
harrisiJun 2, 2026
Just want to say thank you for sharing your project. Very fun, and I wouldn't know about Matthias Wandel's version if not for yours!

Also, both of these tickled my brain in a great way. I think a potentially fun continuation would be to "eyeball" physics. For example, throw a ball and pause the physics before it hits something (ground, object, who knows?) and guess the location. Or show two objects about to collide with certain shapes and masses and guess what one of them will hit first and where.

stronglikedanJun 2, 2026
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.
FinanceFreddyJun 2, 2026
Oh, this is actually fun! How about if you change the target every few seconds to add a bit of pressure.
lbeyerJun 2, 2026
Simple premise, oddly hard to put down.
layer8Jun 2, 2026
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.
ehsangazarrJun 2, 2026
Really fun! I am pretty much blind
ehsangazarrJun 2, 2026
pretty fun!
densekernelJun 2, 2026
https://eyeball.rory.codes/ I was 0.20% off on eyeball. Beat me: https://eyeball.rory.codes
pravjJun 2, 2026
I reached 0.05% and retired for the day.

https://postimg.cc/MXBQqrXf

schuhwerkJun 2, 2026
Nice! Would be nice to see your progress over time (if you got better, also as a function of speed...)
oastpJun 2, 2026
love it, pulls you in after a first try)
wolttamJun 2, 2026
The low contrast of this website hurts my eyeball
ChaseraphJun 2, 2026
Well I suck.
mrroryflintJun 2, 2026
I built it and still suck, don’t feel so bad.
MabustoJun 2, 2026
I love these simple games that take 2 seconds to understand the rules.

Off by 6 on my iPad by mis-clicking. Very satisfying!

mrroryflintJun 2, 2026
Thank you!
harrisiJun 2, 2026
It's interesting that there are, at the time I'm commenting, 11 new users commenting on this submission, some commenting multiple times. I wonder what the effect of "share my score" type pages have on account creation.
hazelnutJun 2, 2026
yes, was thinking the same. but it's also weird that the amount of new users commenting is so much higher here. wonder if that is just not a coincidence.
cdelsolarJun 2, 2026
i got a 0.00% after 3 tries!
HugsboxJun 2, 2026
I didn't think I'd be any good at this. What I didn't expect is how wildly inaccurate I'd be on every single goddamn attempt lmao it's like I completely lack whatever part of your brain is required to do this