Free · new set every day at midnight Eastern
Hard problems, every day.
A daily set of demanding puzzles and subject problems for people who want to be stretched. Deliberate practice, honest scoring, and the technique behind every answer.
No account? Play one category a day as a guest. How it works
Twelve categories
- Ciphers
- Words
- Patterns
- Logic
- Memory & speed
- Spatial
- Mathematics
- Computer science
- Chemistry
- Physics
- Biology
- Economics
A problem of the day in every field
Ciphers, words, patterns, logic, memory and spatial reasoning — plus maths, computer science, chemistry, physics, biology and economics. Same problems for everyone.
Hard at the top
Five tiers per puzzle type, from warm-up to brutal. Adaptive practice follows your rating so you're always stretched.
Learn the technique
Every answer comes with the method behind it: frequency analysis, overlap logic, inclusion–exclusion.
Skill drills
Short adaptive games for the sub-skills — shifting letters, reading binary, dual n-back, mental arithmetic.
Ready for today's set?
It takes about twenty minutes. The clock starts when you open a problem.
Start for free