GUYTU6J wrote: ↑
July 30th, 2020, 5:59 am
Wait, I'm a bit confused of the relationship —
According to the DRH-oscillators.rle, the p128 on the left was found by David Buckingham before November 1991. It features four copies of the dependent p8 variant of R64. So does that mean it probably inspired him to discover the stable, FNG-releasing R64 (and consequently the p256 glider gun) four years later?
I think that's right. Most of the story seems to be told in this article
. The story actually started back in 1973 with Mark Niemiec (see second paragraph) (!).
At almost the same time in 1973, Mark Niemiec was investigating appearance of known common forms (B, R, Lom, Pi, etc) within the histories of these same objects. He showed me a listing of the most promising observation: a B-heptomino run to 70 generations (quite a feat in those days!), where he had highlighted the evolution of a new B-heptomino at generation 64, turned 90 degrees. And since the B-heptomino releases a natural glider in generation 41, period 64, 128, and 256 guns appeared to be an absolute certainty as soon as someone tamed the pesky debris behind this new B! But most work in those days was done manually (gasp!) and this was not a manual job.
Resurrecting Niemiec's old listing of the B-heptomino reproducing itself at generation 64, I set about to create the period 64 gun to start.
I needed a spark source and since most of the neat spark toys that exist now had yet to fall out the search programmes, only period 8 (and subperiods) was practical (Figure-8, Kok's Galaxy, Emulators, Mold, Mazing).
With these tools, the new B-heptomino was quickly isolated, but the new (and unanticipated challenge was to remove the block created by the B-heptomino at generation 15. Adding to this distress, the new B-heptomino makes such a sharp turn that removal of debris block from the previous B-heptomino at generation 57 becomes a problem. Ok, the debris removal process would need to remove the two blocks and the residual debris from the turn reaction.
After a few weeks work, the reaction is found, the P64 gun constructed and lo and behold, the glider produced by each B at generation 41 smashes into one of the Galaxys used. Sheesh, I forgot that the glider passes back through the mechanism! No problem, we'll just find another way to turn a B-heptomino and use these two in combination. More work and the elegant sparking of a B-heptomino to produce the P73 glide symmetry turn; debris dies cleanly, while removing the generation 15 block, and the glider produced by the B removes the block from the previous B. This time we'll test a quarter of the mechanism before building the whole thing. Now the glider just nicks the figure-8 for the P73 turn. Even more work, a P64 turn that removes the debris, both blocks, and the glider.
Attempts to produce period-independent track pieces (bounded only by still lifes) had failed over the previous 23 years to yield much of anything useful. Suddenly (clouds open, sun shines, angels sing) a fluke placement of a block (and subsequent stabilizing blocks), produces the period 64 B-heptomino turn dreamt of in 1973 (as classy and elegant as it was supposed to be). This was the first period independent B-heptomino turn and yielded the P256 gun ... but since the released gliders pass through the mechanism, this is the only period glider gun possible (with a Figure 8, the gliders can be removed, and 4 B's cycled, but defeats the purpose). Ergo, still no period 64 gun!
I like the "clouds open, sun shines, angels sing" part. That kind of discovery doesn't show up very often, but it sure is awesome when it happens.