Compare Claude Opus 4.1 by Anthropic against Qwen: Qwen3.5 Plus 2026-02-15 by Qwen, context windows of 200K vs 1.0M, tested across 27 shared challenges. Updated February 2026.
27 challenges
Tests an AI's ability to solve a simple but potentially confusing logic puzzle
Here is the step-by-step logical deduction:
Analyze the family structure from the brothers' perspective: The problem states that "Each brother has 2 sisters." Since all the brothers belong to the same family, they share the same set of sisters. This means there are exactly 2 girls in the entire sibling group.
Identify the girls: We know one of the girls is Sally. Since the total number of girls is 2, the other girl must be Sally's sister.
Calculate Sally's specific number of sisters: To find out how many sisters Sally has, we look at the total number of girls and subtract Sally herself. $$ \text{Total Girls} - \text{Sally} = \text{Sally's Sisters} $$ $$ 2 - 1 = 1 $$
Conclusion: Sally has 1 sister.
Tests an AI's randomness and creativity
Tests an AI's ability to create detailed SVG illustrations of gaming hardware
Tests an AI's ability to simulate personalities and predict future trends
Tests an AI's humor and understanding of current events
Tests an AI's ability to generate a complete, working landing page
Recreate an interactive, classic Mario level in a single HTML file.
Tests an AI's UI design skills with theming support
Tests an AI's ability to engage in philosophical discourse about AI rights
Generate SVG art of a randomly chosen animal in a setting of its choosing.
Generate a unique and simple recipe with common ingredients.
Create a starter plan for improving long-term health.
