
marrow - scroll to learn
Learn one idea at a time
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Free
About
marrow is a feed of ideas worth keeping.
Instead of an endless scroll of noise, you move through short, self-contained explanations (one concept per screen) across computer science, finance, math, and science. Each card explains a single idea in a few sentences: why appending to a dynamic array is O(1) on average, what the Rule of 72 estimates, and dozens more.
Some cards ask you a question first. Reveal the answer, then tell marrow how well you knew it. The ones you find hard come back sooner; the ones you already know drift further out. That is spaced repetition, built into the scroll, so the ideas you want to keep actually stick.
- One idea per screen, made for short sessions
- Four domains: computer science, finance, math, and science
- Self-grading with spaced repetition, so reviews return at the right time
- Fully offline: no account, no ads, no tracking. Your progress stays on your device.
Scroll to learn.
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What's New in marrow
1.3.0
August 18, 2026
A home screen widget. One concept a day, in three sizes, following the subjects and levels you chose in the app. Tap it to open that card.




