How practice works here
One screen — read it once, then get back to practicing.
Three tiers, hardest first
Every exercise has a tier switcher, and the tiers run in this order on purpose:
- from spec Write it cold, from a plain-English description — no starter code shown. Start here.
- do Do it yourself and get graded — the starting material is shown for reference.
- completion
- see See the solution and study it. Reading it is useful, but studying never counts as solved — you have to actually do it yourself.
Attempt cold at the hardest tier first, and only drop down when you're genuinely stuck. Productive struggle is the point — the easier tiers are a fallback, not the default path.
Meet Mockratis
Get something wrong and Mockratis turns up: a cantankerous old programmer who hand-coded two-phase locking in assembly, has strong opinions about the cloud, and will not, under any circumstances, tell you the answer. He opens with a complaint and then actually teaches — pointing at where your reasoning diverged and asking the question that gets you the rest of the way.
He gets more specific the more you try, and if you're stuck at "from spec" he'll eventually tell you it's time to drop a tier rather than leave you guessing cold. He can't be replied to — the questions are for you to take back to the exercise, not to answer him. And he never reveals the answer, however many attempts it takes. That's the whole point: the goal is that you could re-derive this next month, not that you got past it today.
Spaced repetition decides what's next
Solving something schedules a return visit — sooner if it was a struggle, later once it sticks. Your dashboard always tells you what's due today, so you never have to guess what to practice.