Show HN: Penmentor – Claude marks up your handwritten math like a teacher

Automated excerpt

Press a key while you work by hand: Claude, Gemini or GPT marks your work on the screen like a teacher with coloured pens, gives you hints instead of answers, and shows the idea as a 3Blue1Brown-style animation. Handwriting in xournal++ → one key → the slip is marked on the page → box the integral → an interactive manim animation. (video; for a repeatable recording the pen is scripted and the model's answer is a fixed example. ) I study calculus with a pen tablet in xournal++.

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