With apologies to Mark Niemiec: the following pattern is a placeholder borrowed from his "incomplete" folder, and the accompanying note was

The one useful idea is that the core might be buildable from

spider-on-spider; addition of the wings on the side is left as an

exercise for the masochistic reader.

So to say the least, this is a long way from a finished recipe:

`x = 257, y = 70, rule = LifeHistory`

D54.2D4.2D10.2D11.2D26.2C.2C$D43.D5.D5.D5.D11.D5.D4.D2.D25.C3.C$D2.D

2.4D3.3D2.D3.D.4D9.4D.5D9.D5.D11.D10.D5.3D3.D17.C.C$D.D3.D3.D.D3.D.D

3.D.D3.D7.D7.D5.D5.D5.D11.D5.D3.3D3.D3.D19.2C.2C$3D3.D3.D.D3.D.D.D.D.

D3.D8.3D4.D5.D5.D5.D11.D5.D4.D4.5D20.C.C$D2.D2.D3.D.D3.D.2D.2D.D3.D

11.D3.D5.D5.D5.D11.D5.D4.D4.D6.D16.C3.C$D3.D.D3.D2.3D2.D3.D.D3.D7.4D

5.2D3.2D4.2D4.2D10.2D4.2D3.D5.4D19.2C.2C19$111.2A7.2A$111.4A3.4A$113.

7A2$116.A$46.D5.D31.D29.2C.2C$46.D5.D31.D29.C3.C$37.4D2.4D2.4D8.4D.4D

3.4D.D.2D2.D2.D3.4D2.D17.C.C$36.D3.D.D3.D.D3.D7.D5.D3.D.D3.D.2D2.D.D.

D3.D23.2C.2C$36.D3.D.D3.D.D3.D8.3D2.D3.D.D3.D.D5.3D4.3D21.C.C$36.D3.D

.D3.D.D3.D11.D.D3.D.D3.D.D5.D2.D6.D2.D16.C3.C$37.4D2.4D2.4D7.4D2.4D3.

4D.D5.D3.D.4D20.2C.2C$66.D46.7A$66.D46.7A$116.A16$111.A9.A49.A9.A$

111.A4.C4.A49.A4.C4.A$115.3C57.3C38.D$114.C3.C55.C3.C27.D5.D3.D19.D$

115.3C57.3C20.D3.D7.5D.D.2D8.D3.D7.4D3.3D3.4D$62.D27.D23.5C55.5C19.D

3.D3.D5.D3.2D2.D7.D3.D3.D3.D3.D.D3.D.D$56.D4.2D11.D5.D9.D23.C3.C55.C

3.C19.D.D.D3.D5.D3.D3.D7.D.D.D3.D3.D3.D.D3.D2.3D$56.D5.D9.5D8.4D.D2.D

3.D17.C.C52.3C2.C.C2.3C15.2D.2D3.D5.D3.D3.D7.2D.2D3.D3.D3.D.D3.D5.D$

54.5D3.D11.D5.D3.D5.D.D21.2C.2C51.2C2.2C.2C2.2C15.D3.D3.2D5.2D.D3.D7.

D3.D3.2D2.D3.D2.4D.4D$56.D5.D11.D5.D3.D5.3D22.C.C51.C2.C2.C.C2.C2.C

66.D$56.D5.D11.D5.D3.D5.D2.D3.D16.C3.C55.C3.C68.3D$61.3D11.2D3.2D3.4D

.D3.D2$113.A5.A53.A5.A$114.A.A.A55.A.A.A!

The dart is small enough that it maybe it's time for some fresh thinking about it. Is there a way to optimize a search utility to find construction-friendly predecessors, for example? "Construction-friendly" might mean weighting a search to prefer partial solutions that are P1 in the center, with as few sparks as possible around the edge.

CPU speeds have come along way since lifesrc was written, and so has available memory. Maybe there's some way to use a hash table to recognize and jump past parts of searches that have already been tried. Or it might help to build a very large database of traveling sparks -- i.e., hit still lifes and small constellations with gliders, and record every generation where the result is fairly compact and has just moved to a previously untouched row or column in the last tick.

-- Well, maybe not. Those dart wings are only 7 bits each, but it looks as if any possible predecessors would have interacted with the dart's body in the previous tick, so the traveling-spark idea probably won't work here.