https://watermark02.silverchair.com/stag328.pdf?token=AQECAH...

mentions 3 three alternative interpretations for GRB 250702B:

1. Ultralong Collapsars: These stellar-engine models can explain long durations but struggle to account for the specific timing of this event. Specifically, they cannot easily produce a 12-hour gradual rise in X-rays followed by a multi-hour peak, as the jet would have to fight through a massive progenitor star while its power is still very low.

2. White Dwarf (WD) Tidal Disruptions: While an Intermediate Mass Black Hole (IMBH) disrupting a White Dwarf could theoretically provide the necessary gravity, the numbers do not add up for this specific burst. The timing between flares is too long for a WD scenario, and the total energy required would demand an unrealistically narrow jet. When physical constraints like detonation are factored in, this model is considered highly unlikely.

3. Micro-TDEs (Main Sequence star by a stellar-mass BH/NS): This is considered a competitive alternative that can explain the burst's sub-second variability and long duration. However, it faces two main issues: current afterglow data suggests the surrounding gas density matches an IMBH environment better than a micro-TDE environment, and the burst’s extreme energy would require very high jet efficiency or a very narrow beam.

Suggestions on building a little free library: 1) By far the number one priority: Waterproof. If it's not waterproof, in my opinion you're actually doing a disservice to the community, rather than a service. And have an angled roof for proper drainage. 2) Don't make it too deep. Definitely not more than 18 inches. Probably 15 inches is a good depth. 3) If you can, make two levels: One level for tall books, another level for short books. 4) Don't make it too tiny, because then it's hard to get books in and out of. 5) A good solid stand so it doesn't fall over. 6) A good latch that will resist wind. Magnetic is good. I also like to have a magnet plus a hook that can be used for backup. Also with time it's nice to have the second option in case the shape changes a little and the magnet doesn't work. 7) You might try making a mockup out of cardboard so you can see the physical size and get a sense of how many books will fit. 8) Not a building tip, but: Try to arrange the books to look nice. If you have few books you can face some of them to attract attention.

111011011111110101111101111

and give this output:

101101110111101111101111111

I.e., it's sorting the array [3,2,7,1,5,4]. The machine has 31 states and requires 1424 steps before it comes to a halt. It also introduces two extra symbols onto the tape, 'A' and 'B'. (You could argue that 0 is also an extra symbol because turinmachine.io uses blank, ' ', as well).

When I started writing the code the LLM (Claude) balked at using unary numbers and so we implemented bubble_sort.yaml which uses the tape symbols '1', '2', '3', '4', '5', '6', '7'. This machine has fewer states, 25, and requires only 63 steps to perform the sort. So it's easier to watch it work, though it's not as generalized as the other TM.

Some comments about how the 31 states of bubbles_sort_unary.yaml operate:

  | Group | Count | Purpose |
  |---|---|---|
  | `seek_delim_{clean,dirty}` | 2 | Pass entry: scan right to the next `0` delimiter between adjacent numbers. |
  | `cmpR_*`, `cmpL_*`, `cmpL_ret_*`, `cmpL_fwd_*` | 8 | Comparison: alternately mark units in the right (`B`) and left (`A`) numbers to compare their sizes. |
  | `chk_excess_*`, `scan_excess_*`, `mark_all_X_*` | 6 | Excess check: right number exhausted — see if unmarked `1`s remain on the left (meaning L > R, swap needed). |
  | `swap_*` | 7 | Swap: bubble each `X`-marked excess unit rightward across the `0` delimiter. |
  | `restore_\*` | 6 | Restore: convert `A`, `B`, `X` marks back to `1`s, then advance to the next pair. |
  | `rewind` / `done` | 2 | Rewind to start after a dirty pass, or halt. |

I'm curious if anyone can suggest refinements or further ideas. And please send pull requests if you're so inclined. My development path: I started by writing a pretty simple INITIAL_IDEAS.md, which got updated somewhat, then the LLM created a SPECIFICATION.md. For the bubble_sort_unary.yaml TM I had to get the LLMs to build a SPEC_UNARY.md because too much context was confusing them. I made 21 commits throughout the project and worked for about 6 hours (I was able to multi-task, so it wasn't 6 hours of hard effort). I spent about $14 on tokens via Zed and asked some questions via t3.chat ($8/month plan).

A final question: What open source license is good for these types of mini-projects? I took the path of least resistance and used MIT, but I observe that turingmachine.io uses BSD 3-Clause. I've heard of "MIT with Commons Clause;" what's the landscape surrounding these kind of license questions nowadays?

Comments URL: https://news.ycombinator.com/item?id=47008236

Points: 12

# Comments: 2

"What began as a read-it-later app evolved into something much bigger. After Mozilla acquired Pocket in 2017, we invested in building our content curation and recommendation capabilities so people everywhere can discover and access high quality web content. While Pocket is shutting down, we will continue to invest in this promise—through the New Tab experience, our email newsletter, and more."

5k2/pp4pp/4pp2/1P6/8/P2KP3/5PPb/2B5 w - - 0 30

Full PGN here:

[Event "Spassky - Fischer World Championship Match"] [Site "Reykjavik ISL"] [Date "1972.07.11"] [EventDate "?"] [Round "1"] [Result "1-0"] [White "Boris Spassky"] [Black "Robert James Fischer"] [ECO "E56"] [WhiteElo "?"] [BlackElo "?"] [PlyCount "111"]

1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4 5. e3 O-O 6. Bd3 c5 7. O-O Nc6 8. a3 Ba5 9. Ne2 dxc4 10. Bxc4 Bb6 11. dxc5 Qxd1 12. Rxd1 Bxc5 13. b4 Be7 14. Bb2 Bd7 15. Rac1 Rfd8 16. Ned4 Nxd4 17. Nxd4 Ba4 18. Bb3 Bxb3 19. Nxb3 Rxd1+ 20. Rxd1 Rc8 21. Kf1 Kf8 22. Ke2 Ne4 23. Rc1 Rxc1 24. Bxc1 f6 25. Na5 Nd6 26. Kd3 Bd8 27. Nc4 Bc7 28. Nxd6 Bxd6 29. b5 Bxh2 30. g3 h5 31. Ke2 h4 32. Kf3 Ke7 33. Kg2 hxg3 34. fxg3 Bxg3 35. Kxg3 Kd6 36. a4 Kd5 37. Ba3 Ke4 38. Bc5 a6 39. b6 f5 40. Kh4 f4 41. exf4 Kxf4 42. Kh5 Kf5 43. Be3 Ke4 44. Bf2 Kf5 45. Bh4 e5 46. Bg5 e4 47. Be3 Kf6 48. Kg4 Ke5 49. Kg5 Kd5 50. Kf5 a5 51. Bf2 g5 52. Kxg5 Kc4 53. Kf5 Kb4 54. Kxe4 Kxa4 55. Kd5 Kb5 56. Kd6 1-0