Track 01
Object-Oriented Programming
Build characters from a class, then watch every instance keep its own state.
- Classes & objects
- self & __init__
- Inheritance
- Properties
- Polymorphism
- Dataclasses
- MRO
- ABCs & Protocols
- SOLID
Play to learn Python OOP & data structures
Fight bugs. Earn XP. Level up your Python.
Every level is a battle. Beat the bug, build your combo, unlock companions and climb the ranks while you master Python OOP and data structures.
A stack and a queue you can operate appear here. Your browser could not start the 3D view, but every lesson works without it.
How it works · 1 / try it
See the idea. Then name it in code.
Every operation you press is applied to a real list and written out as Python on the right. Nothing is scripted: the answer is checked against the target, not against a recording.
Reshape the stack
The stack starts as [3, 5, 1]. Use only push and pop to turn it into the target below.
target = 3
8
A stack only lets you touch the top item. Which items stand between you and the 3?
Value to push
0 operations · This is a browser simulation of list.append and list.pop. The sandboxed Python runner for real code arrives with the coding arena.
Two tracks · pick either, or both
Objects on one side. Structures on the other.
Your level in one track never decides your level in the other. Jump straight to a single topic like hash maps without clearing anything first.
Track 02
Data Structures
Operate the structure, see it change, then implement it yourself.
- Lists & dicts
- Stacks & queues
- Linked lists
- Hash tables
- Trees & BSTs
- Heaps
- Graphs, BFS & DFS
- Tries
- Big-O
The journey · a real map, not a list
Walk the trail. Earn stars. Beat the clock.
Every tier is a trail of zones. Each zone has levels, then a timed quiz that pays out for accuracy and speed. Finish a tier and the next one is waiting, or jump to any tier you like.
Built around real misunderstandings
The Python bugs everyone hits. We teach those first.
Each lesson targets a genuine trap: the shared list, the sneaky +=, the method resolution order. Predict the output, then see why Python does what it does. Every answer here was run in real Python.
Three tiers · three different games
The format changes as you grow.
Each tier is built differently, not just made harder.
Beginner
Friendly explanations, optional hints, and plain language.
- Multiple choice and predict-the-output
- Visual puzzles you operate by hand
- Code ordering and guided coding
- Short independent coding challenges
Intermediate
Mostly code. You implement structures, debug, and explain the cost of what you wrote.
- Implement structures against multiple test cases
- Debugging and applied problem-solving
- Complexity explanations
- Conceptual quizzes only where they genuinely help
Advanced
Real engineering work, judged by hidden tests and complexity requirements.
- Design, implement and optimise
- Advanced debugging and refactoring
- Architecture and extensibility tasks
- Follow-up technical explanations
Rewards & leaderboard
Companions that cheer you on. Ranks that stay honest.
Collect original companions as you learn. Click one to see it react. Free players start with the first three; Nova unlocks the rest. Rankings come only from verified results on the server.
Divisions you earn
Leaderboards are split by track, tier, country and season, with deterministic tie-breaks, a podium for the top three, and your own row pinned if you are further down.
Scored on the server
Rank points are calculated server-side from verified results, and each challenge earns them once per season. Easy-question farming does not move you up.
Nothing to buy
Companions and premium bonuses change adventure XP and cosmetics only. They can never add to competitive rank points.
Interview Simulator · planned
Practise the interview before the interview.
Hints, pauses and explanations are all on. Built for learning, with recommendations on what to revisit.
- Beginner: a friendly Skill Quest of short exercises
- Intermediate: a screening with 1–2 coding tasks and complexity questions
- Advanced: complex coding, optimisation follow-ups and OOP design
Timed, no hints, and a formal result. Scored by tests and a published rubric, not a mystery number.
- Correctness comes from visible and hidden test cases
- Complexity and code quality use defined criteria
- An AI interviewer will be optional and clearly labelled. Voice is not available.
Sample rubric100 pts
Correctness
visible + hidden tests50
visible + hidden tests50
Complexity
meets stated O(·) target20
meets stated O(·) target20
Code quality
naming, structure, edge cases15
naming, structure, edge cases15
Explanation
reasoning, reviewed against criteria15
reasoning, reviewed against criteria15
Illustrative weights. Final rubric is published with the feature.
Free & Nova
Learning stays free. Nova adds depth and style.
All difficulty levels, the real editor and the leaderboards are free. Nova never buys rank.
| Feature | Free | Nova |
|---|---|---|
| Core curriculum, every tier and topic | Included | Included |
| Real coding editor, tests and explanations | Included | Included |
| Leaderboards and earnable achievements | Included | Included |
| Basic companions and learning analytics | Included | Included |
| Mock interview sessions | Selected sessions | More sessions, extended reports |
| Practice programs and review history | Standard | Personalised, deeper history |
| Cosmetics: rings, banners, themes, username effects | — | Included |
| Bonus adventure XP (never rank points) | — | Included |
Prices are shown in full before you pay, and every payment is processed securely by our payment provider. Nova time never renews on its own, and your plan is only ever marked active after the payment provider confirms it.
Ready to see how it works?
Start with a stack. End with code you understand.