Comparison

Euclidea vs Nonograms Katana

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Euclidea

Engage in geometric construction puzzles based on Euclidean principles. Solve increasingly difficult challenges using innovative tools, with options to explore, get hints, and compete with friends. Unlock new levels by earning stars or purchase an in-app item to remove restrictions.

Highlights
  • 156 geometric puzzle levels
  • 10 innovative construction tools
  • Explore mode with hints
  • Dynamic drag, zoom, and pan interface
  • Game Center competition
  • Unlockable tools and shortcuts
Features
Read full description

Euclidea is geometrical puzzles based on classical Euclidian constructions. > 156 Levels: from very easy to really hard > 10 Innovative Tools > "Explore" Mode and Hints > Easily Drag, Zoom & Pan > Compete with Friends via the Game Center > No Advertising! New levels are unlocked as you solve the previous ones. You can complete the whole game only if you earn all the stars (L, E, and V). But you can buy an IAP that removes this restriction. Find more useful hints on Euclidea on our site: https://www.euclidea.xyz/faq. “Euclidea has been shown to help with imagination, intuition, and logic, all wonderful skills to develop.” – appPicker “Euclidea is an absolute joy to play…it’s a game that every math student should have and, in an ideal world, every adult should like.” – Non-Trivial Games ***About Euclidea*** Euclidea is a brilliantly original way to learn about, explore and have fun with Euclidian Constructions! Your task is to solve interesting challenges by building geometric constructions with a straightedge and compass. If you design the most elegantly simple solutions in the least number of moves, you’ll earn the highest scores. Solutions are scored in lines (L) and elementary Euclidean constructions (E). ***Start Simple and Get Smarter!*** Don’t worry if you aren’t a math wizard. Euclidea starts out with simple challenges that guide you through the basics. Once you master the fundamentals, you’ll move on to tougher, more mind-bending challenges such as inner/outer tangents, regular polygons, and more. There are 120 unique challenges in total, which are organized in packs for simpler navigation. ***Add Constructions to Your Interface*** When you learn certain significant constructions – such as angle bisectors, non-collapsing compass, and so on – they are automatically added to the Euclidea interface’s shortcut, which helps you save time and allows you to create clean, uncluttered drawings. ***Easily Drag, Pan & Zoom*** Euclidea-created constructions are completely dynamic. As such, you can drag to adjust angles, lines, radii and so on. You can also easily zoom and pan. This not only makes the experience more interactive, but it allows you to more deeply grasp the relationships between geometric elements, explore various possibilities, and analyze errors. ***Instant, Automatic Precision*** Don’t worry about spending time or effort trying to achieve perfect precision, because Euclidea automatically handles that task by pinning points, lines and circles to the app’s clean interface. ***Compete with Friends*** Who said that math isn’t a competitive sport? Challenge your friends to see who can come up with the most elegant solutions, and track your achievements and rankings via the Game Center. ***Additional Special Features*** > A helpful “Explore” mode that allows you to see the figure you need to construct > An inventory of tools that you create as you progress – you’ll need these to solve future challenges > Some challenges can be solved in more than one way, which means you can try a different approach and have even more fun ***Questions? Comments? Send in your inquiries and stay up-to-date on the latest Euclidea news at https://www.euclidea.xyz/

About

Nonograms Katana

Engage in logic puzzles where you fill cells based on numerical clues to reveal hidden pictures. This app offers a vast collection of puzzles, tools for marking cells, and options to create and share your own challenges.

Highlights
  • 1001 nonogram puzzles
  • Create and share custom puzzles
  • Black-and-white and colored puzzles
  • Puzzles sorted by size
  • Hints and undo/redo functionality
  • Cloud save and achievements
Features
Read full description

Nonograms Katana: Sharpen your mind! Nonograms, also known as Hanjie, Griddlers, Picross, Japanese Crosswords, Japanese Puzzles, Pic-a-Pix, "Paint by numbers" and other names, are picture logic puzzles in which cells in a grid must be colored or left blank according to numbers at the side of the grid to reveal a hidden picture. The numbers are a form of discrete tomography that measures how many unbroken lines of filled-in squares there are in any given row or column. For example, a clue of "4 8 3" would mean there are sets of four, eight, and three filled squares, in that order, with at least one blank square between successive groups. To solve a puzzle, one needs to determine which cells will be boxes and which will be empty. Determining which cells are to be left empty (called spaces) is as important as determining which to fill (called boxes). Later in the solving process, the spaces help determine where a clue (continuing block of boxes and a number in the legend) may spread. Solvers usually use a dot or a cross to mark cells they are certain are spaces. It is also important never to guess. Only cells that can be determined by logic should be filled. If guessing, a single error can spread over the entire field and completely ruin the solution. Features: - 1001 nonograms - All puzzles are free - All puzzles tested by computer program and have unique solution - Black-and-white and colored - Nonograms sorted by groups from 5x5 to 50x50 - Download puzzles sent by other users - Create and share your own puzzles - 15 free hints per puzzle - Use crosses, dots and other symbols to mark cells - Auto cross out numbers - Auto fill trivial and completed lines - Auto save; if you stuck you can try another puzzle and come back later - Zoom and smooth scrolling - Lock and zoom number bars - Lock current puzzle state, check assumptions - Customize background - Optional cursor for accurate picking - Undo and redo - Share result pictures - Save game progress to the cloud - Achievements and leaderboards - Screen rotation - Suitable for phones and tablets VIP Features: - No Ads - View Answer - 5 extra hints per puzzle The Guild Expansion: Welcome to the Adventurers Guild! By solving puzzles, you will get loot and experience. You will have weapons that allow you to deal with puzzles much faster. You will be able to complete quests and receive a reward. You will have to rebuild the settlement and collect the lost mosaic piece by piece. The Dungeon Expansion: Game in a game in a game. Isometric turn-based RPG. What adventurer doesn't dream of exploring a dungeon? site: https://nonograms-katana.com facebook: https://www.facebook.com/Nonograms.Katana

Screenshots

Euclidea4 screens
Nonograms Katana4 screens

Verdict

The call

The clearest difference is ratings volume: Nonograms Katana at 6.8K against Euclidea's 938. Euclidea's advantage is iOS requirement (8.0 vs 14.0). On price, rating, review sentiment and update cadence there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Euclidea sells 6 one-off in-app purchases and Nonograms Katana sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.8 for Euclidea against 4.8 for Nonograms Katana. That said, the two scores are not equally well evidenced: Nonograms Katana has 6.8K ratings behind it against 938, so its average is the more settled of the two. Written reviews are what separate them: 86% of Euclidea's written reviews are positive against 83% of Nonograms Katana's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 months. The most recent releases landed on November 4, 2026 and November 2, 2026 respectively.

Scorecard2 real differences · 8 level
Euclidea versus Nonograms Katana: the parameters behind the verdict, then further details
ParameterEuclideaNonograms Katana
PriceFreeFree
Rating4.8 (938 ratings)4.8 (6.8K ratings) — better
Positive reviews86.1% of reviews — better82.9% of reviews
Number of ratings9386.8K — better
Update frequencyEvery 3 monthsEvery 3 months
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS8.0 — better14.0
Further details — not scored
Size223 MB27 MB
Age rating4+12+
DeveloperHORIS INTERNATIONAL LIMITEDUcdevs Interaction DOO

Customer experience

Euclidea

All ratings937 ratings
Positive96.5%
Neutral1.2%
Negative2.3%
Written reviews397 reviews
Positive86.1%
Neutral3.5%
Negative10.3%

Nonograms Katana

All ratings6,245 ratings
Positive97.2%
Neutral1.7%
Negative1.1%
Written reviews339 reviews
Positive82.9%
Neutral5.3%
Negative11.8%

User reviews

Euclidea

From 938 App Store ratings

What we love

  • 🚀 Excellent interface
  • 🚀 Smooth controls
  • 👍 Challenging and engaging puzzles
  • 👍 Helps learn and improve geometry skills
  • 👍 No ads or in-app purchases

Room to improve

  • 🐛 App crashes on launch for some users
  • 🐛 Circle tool not snapping to points properly
  • 🐛 Solutions not always accepted even when correct
  • 🔒 Locked levels require in-app purchases to access

Nonograms Katana

From 6.8K App Store ratings

What we love

  • 👍 Lots of puzzles
  • 👍 Customizable settings
  • 👍 Minimal ads
  • 👍 Challenging puzzles
  • 👍 User-created puzzles

Room to improve

  • 🐛 Occasional crashes
  • 🐛 Puzzle progress loss
  • 🐛 Ads not working
  • 🐛 Freezing issues
  • 🐛 Compatibility problems

Bugs and requests

Euclidea

Reported bugs

3 issues
  • App crashing on launch
  • Circle tool not snapping to points
  • Solutions not being accepted correctly

Requested features

5 requests
  • Offline mode support
  • Ability to mark points on free draw
  • Protractor feature
  • More supplemental educational content
  • Ability to see when multiple solutions exist

Nonograms Katana

Reported bugs

5 issues
  • Puzzle progress not saving
  • Puzzle images not loading
  • Freezing/crashing on larger puzzles
  • Ads not playing properly
  • Compatibility issues with newer iOS versions

Requested features

7 requests
  • Dark mode option
  • Ability to rearrange/move puzzle pieces
  • Difficulty ratings for puzzles
  • Automatic line/row completion
  • Ability to follow/subscribe to users
Show 2 more
  • Notification system for new puzzles
  • Diagonal line drawing tool

In-app purchases

6 purchases

Euclidea

One-time6
  • Unlock the Rest Levels$0.99
  • Unlock the Rest Hints$0.99
  • Thanks to developers$0.99
Show 3 more
  • Night Mode$0.99
  • Many thanks to developers$4.99
  • Many, many thanks to developers$49.99
3 purchases

Nonograms Katana

One-time3
  • 80 Hints$0.99
  • 200 Hints$1.99
  • VIP version$5.99

Questions

Is Euclidea free?
Euclidea is free to download, with in-app purchases available.
Is Nonograms Katana free?
Nonograms Katana is free to download, with in-app purchases available.
Which has better reviews, Euclidea or Nonograms Katana?
Nonograms Katana is rated higher. Euclidea averages 4.8 out of 5 from 938 ratings, while Nonograms Katana averages 4.8 from 6.8K ratings.
Do Euclidea or Nonograms Katana have ads?
Neither Euclidea nor Nonograms Katana shows ads.
Which is updated more often, Euclidea or Nonograms Katana?
Euclidea ships an update every 3 months, and Nonograms Katana every 3 months. Most recently, Euclidea was updated on November 4, 2026 and Nonograms Katana on November 2, 2026.

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