Show HN: Newton's Orchard – Browser-based space/gravity playground https://ift.tt/8TzdN3v

Show HN: Newton's Orchard – Browser-based space/gravity playground Hi HN! My son spent a lot of time in 5th grade playing with the 2-dimensional PhET gravity/space sims[1]. His STEM class uses it, and he was playing with it at home, and has been looking for more. I found several space sims/playgrounds online, including NASA's Eyes on the Solar System[2], but nothing that seemed to offer a real progression from what he was getting out of the PhET sims, so I built Newton's Orchard over the summer for him. https://ift.tt/rglLDpx The source is also published at https://ift.tt/81gsXuB It features deterministic time scrubbing, all bodies are editable, different preset systems and experiments, missions to complete (complete 3 to unlock the blackhole object type and mission), and a gallery for user submissions. I would very much appreciate feedback from HN - particularly from the lens of making it engaging and illuminating for students, and anyone that would like to just get a feel for how gravity works. Thank you! [1] https://ift.tt/pbqKZla... [2] https://ift.tt/YyD0z9T https://ift.tt/rglLDpx September 1, 2026 at 11:43PM

Show HN: Semantic Overlays – an NX bit for LLM prompt injection (live demo) https://ift.tt/Qm8YsK4

Show HN: Semantic Overlays – an NX bit for LLM prompt injection (live demo) I've built a new method for steering LLMs called Semantic Overlays, small trained adapters on a frozen model which change how its perceives a piece of its context. The most readily applicable usage is to mitigate prompt injection, and it lets us take a very-injectable Qwen-3.5-9B to SOTA scores on all the prompt injection benchmarks I could find. (They are only blackbox attacks, but I did NOT train on anything like them — whitebox attacks are out of scope for this paper) I'm excited for you to play with the tech — see if YOU can break it! (let me know if you can) Paper at https://ift.tt/Ah9erJX if you want to read more about it, code at https://ift.tt/a9wvnZR , adapters at https://ift.tt/X7VWDKl... Also https://ift.tt/vHP63nw if you wanna watch a little video I made! https://semantic-overlays.vercel.app/ September 2, 2026 at 12:40AM

Show HN: Running 104GB Qwen3.8-Flash-Next on 48GB Mac with at ~12 tok/s https://ift.tt/M4IhHVX

Show HN: Running 104GB Qwen3.8-Flash-Next on 48GB Mac with at ~12 tok/s I built slotstream, a way to run Qwen3.8-Flash-Next 4-bit on a low-memory mac starting from 16GB, a 125B parameter model that would need 100GB+ memory/RAM, thanks to expert-offloading/ssd-streaming. Easy to install/update, and mac-native using MLX and Swift. It ships with auto-mode, which makes a good tradeoff between memory usage and speed. I'll be implementing and porting the MTP module for speculative decoding next https://ift.tt/Nl6hi4y September 1, 2026 at 11:42PM