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Euclid: The Game (euclidthegame.org)
246 points by mpwarres on June 20, 2014 | hide | past | web | favorite | 82 comments

Reminds me of this game: http://www.sciencevsmagic.net/geo/# which seems to be a lot less buggy.

Cool game, well made, but it's driving me nuts. I'm stuck on 3/40 - I've created the enclosing circle for "in origin circle" but game doesn't want to acknowledge it. Clearly I'm doing something wrong....

"in origin circle" means that it has to be circumscribed by a circle with a center on one of the two starting points

Edit: It actually has to be inside of the circle made centered on one of the starting points and with the other starting point on the circle.

thanks for the link. I had lost this game in the mists of time.

I'll give credit to OP's game however, giving you new tools once you have proved how to do something is great!

Exactly what I was thinking

Just gave it a go. Quite a fun game actually. My compliments to the author. Some feedback that may be of use :

1) Use thicker lines, preferably in a color that contrasts better with white (although it'll be fine if the segment width is 2-4 pixels)

2) Support for drag + snap-to-intersect/vertex UX rather than click only. I instinctively tried this first.

3) Some sort of progress tracking (local storage or user accounts even perhaps)

Anyway, great idea and a promising start!

One more UI request: Given two points, there are two possible third points on an equilateral triangle, and no clear way to choose between them.

Great game, though. I'm on level 5 and having a lot of fun.

seems like the third point will follow the anticlockwise norm

Hey, you're right. Maybe clearer messaging is the answer. I had no idea that that was the norm.

I'm working on some of those suggestions here: http://euclidthegame.org/Level1anew.html

Thanks for your feedback!

An eraser to remove lines and segments would be useful too.

Yeah, some of the later ones just get cluttered and it can become difficult to click on the intended point.

Right click.

Hm, seems to only work on some levels.

Reminds me of [0], only with worse controls.

[0] - http://sciencevsmagic.net/geo/

I'm working on the controls. Let me know what you think: http://euclidthegame.org/Level1anew.html

That's a lot better. I'd like to see it try to snap when dragging. I notice I can click once (compass) and click again on a point, but a click-drag to a point doesn't seem to snap to the point.

From the icons, it looks like this may be using Geogebra[1] under the hood. It's a really polished little tool for exploring geometry.

[1] http://www.geogebra.org/cms/en/

Good timing, I just posted the same.

That's fun and educational.

Minor UI feedback:

The undo button moves when you click it which is annoying if you intend to step back 2 or more steps.

Also if you do a partial action and press undo it undoes the partial action and the previous one.

It looks like Esc is the intended "nevermind" button, but it isn't obvious.

That reminds me of google/trimble sketchup. It always annoyed me.

Another minor UI feedback: the yellow against white is very low contrast and difficult to see on my display.

I recently bought a copy of Euclid and it's been sitting on my bookshelf, waiting for that ever-receding "when I have the time." It's like the author set out to give me the most perfect and thoughtful birthday present. :)

What's the book you're referencing?

Presumably Elements; though Euclid wrote others, it's the most famous and relevant to the OP.

I went through couple levels before I realized I got more tools as I go on. Was using just intersect, segment,and compass and things were getting crowded.

If it was good enough for the ancient Greeks, it should be good enough for you.

Time to crack out the papyrus and stylus and turn off the computer?

Warning: if you are stuck on #19, there is a bug. For some reason it won't let you make points at the intersections you need to complete it.

There is a bug, but you can hack your way around it and still solve it. It's like 2 problems in one!

well thanks for the tip... but I'm stuck on #19

... because I'm stuck on #19


I think dashed lines for rays would reduce a lot of visual clutter.

Anyway, I long for the day when someone writes a similar toy for a non-Euclidean plane.

Reminds me of this https://play.google.com/store/apps/details?id=com.wewanttokn...

The author could perhaps learn a bit about leveling from it, to make it more accessible to people trying to learn geometry (if that is the goal?)

Does that cover all of Euclid's elements?

I wanted to go through the Elements, but it wasn't clear how I could do it using a straight edge and compass. I couldn't find much guidance online.

I love this stuff. If this is "thinking geometrically" how does that compare to other forms of problem solving?

Very nice game.

One problem for me is that by default the comments from other users are shown, sometimes with the solution for the level.

I'm struggling on 17. There is no circle that intersects both A and B that is tangential to the line. That's how I interpret the instructions for that level, anyway. However, it seems there should be an infinite amount of circles that are tangential to the line that can intersect A.

I figured it out. I was a bit confused in my assumption.

The circle is supposed to be tangent to the line at B.

Is that to mean tangential to anywhere on the line that intersects B, or B is the point at which the circle is tangential to the line that intersects B?

the latter

Looks cool! I think math needs to be taught in that kind of style, where people learn by doing it. I would be interested in having something similar to that on my site, Learneroo.com. One suggestion: start people off by walking them through easy challenge so they learn the interface.

This game is very similar to my first year of college mathematics -- studying Euclid's Elements and working through the proofs. I look forward to the game version of my sophomore year -- Apollonius' conic sections and Ptolemy's astronomy.

I was thinking the same thing... But Newton and Lobachevsky make for a much more challenging 3rd and 4th edition.

I'm not sure about you guys, but I'm not getting any feedback whatsoever. I've measured it with all the tools I can find, but I'm not getting any "Well done" or any link to the next level. Any thoughts?

It is important to not guess.

You need to use the tools provided to create something that is guaranteed to be what is asked for.

For instance in the first level you aren't given a ruler, so you need to figure out how to do the level without using one.

Well, no shit. But I'm saying I constructed an equilateral triangle but the game wasn't recognizing it. After reloading the page a few times it finally started giving feedback, like thickening the line when moving over it (which wasn't happening before), letting me actually place the dot on the intersection between the two circles

Maybe I'm blind, but I can't find the link to level 2 when I solve level 1.

Ah, so "Well done" doesn't mean you're actually done. I needed to actually draw the lines between the three points to get to the next level.

Completed all levels and produced this spoiler.


Mind blown! very good idea,the controls are a bit rough,but it could be a great tool to teach geometry and trigonometry in general.I went up to level 4,do you "support" tangents?

I wonder what other mathematical axiom sets can be pretty much directly translated in a game like that. Maybe something from calculus, topology or knot theory.

Deontic logic! "Prove that killing Mr. A is incompatible with the categorical imperative. Also supports undo and redo."

For algebra there is http://dragonboxapp.com/ - my 5yo son loves it.

RollerCoaster Tycoon: Trolley Problem Edition

Cool. What is the relation to http://web.geogebra.org/app/ ?

Great game! I'd love to see other peoples' solutions once I finish mine.

Does this have anything with the old ios game by Frank Li and Jason Ma?

Nice game! I think it could make geometry more fun for students.

Awesome. Definitely forwarding to all the teachers I know.

dammit, I'm stuck on 11. Has anyone got a solution?

Compass2 is your friend.

Wow, totally did not notice when Compass2 appeared, probably complicated several of my solutions quite a bit...

Ahhh, I hadn't ever used Compass2 yet, I'll have to check it out, thanks.

Great, now I wish there were more than 20 levels! :p

Level 20 is hard.

Really hard. Any hints?

Great game! Waiting for more levels...

How many levels are there?


Awesome game!

Really cool game and great idea, there's some good educational potential here. I'm looking forward to exploring Euclid's proofs again in this digital format. This easily beats dilly-dallying with a real-life compass.

Can someone please explain to me why doing high school-level technical drawing homework is considered a fun game now?

Because it is an interactive experience that people enjoy/find fun, and there is a win condition.

I think that fits the requirements for a "fun game".

Also wouldn't a CAD program have bisect and what this calls compass2 from the get go?

For some reason I was not expecting HN adults to be surprised/bemused over high school material. My bad, I guess.

Is it the norm this days to use CAD in technical drawing courses? Mine were strictly hand-drawn.

My high school class had hand drawn first semester, autoCAD second semester. (I happened to only be taking the second semester, because I needed another class to fill that semester, so I personally only experienced the autoCAD component)

You think walking through Euclid is done in high school drafting?

From my comments you can see that it is in my experience, and my school was not top-rated at all. It was wrong of me to assume everyone else had the same experience.

You did geometric proofs in drafting class?

I'm not even sure I know what a geometric proof is, so I'd say no? Our teacher would just ask us to solve this sort of exercises with a compass and a ruler, and then he'd grade the tests by checking whether the process to reach the solution made sense (i.e.: I'm pretty sure that level 20 was one of the questions in my midterms). He would have explained the resolutions for most of them in previous lectures, but others were new to us. I can't remember if an additional written proof was required.

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