Looking for a challenge that will build your abstract thinking skills? Try The Hamiltonian Circuit, a fun, relaxing puzzle game that's easy to learn and tough to master.

Find a path that visits every square in the grid, avoiding walls and never crossing itself, to create one continuous circuit.

To get the hang of things, start with one of the simple 4x4 grids. Plot your moves carefully. Try to think ahead; not just by one square, but by four or five. If you think you've made a mistake, trace back over your line. It will disappear.

If you really get stuck, press Hints. Any mistakes will turn red, then disappear. But if you're on the right path, we'll add a line.

There's only one solution for every puzzle. When you find it, you'll know.

Puzzles start with 4x4 grids and go all the way to 20x20. The bigger puzzles are very challenging and can take hours to solve. If you have to quit in the middle of one, don't worry: your progress is automatically saved.

Many find working on these circuits meditative; others reach for the ibuprofen. But no matter which camp you find yourself in, know you're exercising your abstract thinking skills and challenging your brain in ways that actually matter.

Inspired by a puzzle created by Irish mathematician William Rowan Hamilton in 1856, these circuits start off easy and get hard. Really hard. Good luck!

What’s New

Version 1.1.8

We fixed an issue with purchasing single puzzle packs. Thanks to the people who reported that issue!

Ratings and Reviews

4.4 out of 5
16 Ratings

16 Ratings

Dr Ponyo ,

Great, but a bit broken

Amazing game, but when I try to buy an individual pack, I’m unable. I click on “Buy” but nothing happens. Will amend review when fixed!

Developer Response ,

We found and fixed the problem. Version 1.1.8 is now available with the fix. Thanks very much for reporting this!

arista80 ,

Great game.

Great game. Adding 2 features would make it perfect. 1) An undo button, with the ability to undo an unlimited number of moves. 2) “Guess” mode. Sometimes you get to a point where you can’t figure out the next move to make. In those cases it would be super useful to be able to switch to guess mode where the lines you draw are a different color or something. If you proceed with drawing additional lines after the guess and encounter a contradiction you know your original guess was wrong and you can then undo all your guess moves and try something else.

Developer Response ,

Thanks for the great ideas! We'll have guess mode (also known as pencil mode) out soon.

jjthejetplane246 ,

Hitting “Buy” Causes Crash (Edit: Fixed!!)

First off, I love this game, it’s an excellent puzzler and gives the same puzzle high as the likes of sudoku.

However, when I went to buy all packs on my iPhone XS Max, I hit “Buy” and the app crashes. This continues to happen after restart the app. I want to buy all the content for $4.99, but it won’t let me!

I will definitely amend my rating to 5 stars if this issue is fixed.

Edit: Updated rating to 5 stars. Within a couple days of this review going live, the developers patched the game to fix this bug. Amazing turnaround. As a software developer myself, I love seeing this attention to customers. Wish I could rate higher than 5 stars but hopefully the $4.99 I spent to buy the packs is token enough.

Developer Response ,

Sorry about that, but it's fixed in version 1.1.3, which went live a few hours ago. Thanks for reporting it! We're always eager to hear not only about any problems you encounter, but also about any features you'd like to see.

App Privacy

The developer, Good Thinking Games, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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