Case study / 03
Retro Quest
C++17 / Exact RTP / Monte Carlo
A playable slot prototype backed by an independent C++17 probability engine and two complementary verification methods.
← All projectsChallenge
Create transparent game mathematics and verify that the designed behaviour matches the implemented outcome space.
Contribution
Extended an initial candidate exercise into a self-contained public project with a C++ math engine, exact enumeration, Monte Carlo verification and a zero-dependency playable web demo.
Delivery process
From complexity to evidence.
The process changes with the domain, but ownership remains visible from problem definition through verification.
Define the model
Specified symbol weights, fixed reels, payout rules and the collection reward before verifying the implementation.
Enumerate exactly
Evaluated every 22³ reel-stop combination—10,648 outcomes—to calculate the theoretical result.
Simulate independently
Ran a separate 1,000,000-spin Monte Carlo path to detect implementation or modelling disagreements.
Expose the reasoning
Published the C++ engine, reward explanation and playable interface so reviewers can inspect more than a screenshot.
Evidence
What can be verified.
- 10,648 outcomes exhaustively enumerated
- 1,000,000-spin Monte Carlo simulation
- 89.9% verified RTP against a 90% target
- Independent RNG and fixed reel-strip design
- Base and collection-reward contributions separated
- Playable zero-dependency browser demonstration
Key decisions
01Exact enumeration is the source of truth for the finite outcome space.
02Monte Carlo is used as an independent implementation check, not as a replacement for exact calculation.
03Near-miss presentation uses only real reel positions; results are never altered after RNG selection.
04The public repository removes recruiter-specific and confidential references from the original exercise context.
Outcome
The two verification paths converge on approximately 89.9% RTP, providing a compact, inspectable demonstration of C++, probability and responsible game-math reasoning.
The core began as an AGS candidate exercise. The C++ engine, dual verification, documentation and public edition were independently extended after the assessment.
- C++17
- Probability
- Statistics
- Monte Carlo
- JavaScript
- HTML
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