New c/5 spaceship

Over a year ago, when this web page was just starting up, Tim Coe found the first c/5 orthogonal spaceship, appropriately dubbed "the snail" by David Griffeath in his Primordial Soup Kitchen. David Bell has now found a much smaller c/5. Though it lacks the biological synchronicity of Coe's discovery, it makes up for this with some useful sparks.
From: "David I. Bell"
Subject: New period 5 c/5 spaceship with sparks
Date: Mon, 14 Apr 1997 17:58:05 +1000

Today I found a new reasonably small period 5 c/5 spaceship:

The spaceship is short and symmetrical with an empty column between them. Only in one phase do the two halves react with each other, and that is just to suppress a cell. It turns out that the edge of the spaceship can also do this suppression, and so a flipped copy of the component will also work. But you then need to terminate THAT component, however. You can continue this arbitrarily often, but finally need the end component to finish it. An example of this is the following:

This ship has some nice sparks at the edges and back. So you would expect that it might do nice things to gliders, blocks, and other stuff. It can at least do a little bit. Here is a reaction in which a glider is turned into a block by one c/5 ship, and then is deleted by a second one:

But I didn't find any other useful reactions with gliders, other than deleting them. (There are lots of ways to do that.) The hope of making a new glider and thus making a puffer out of this isn't realized. I even tried a little bit using two of the spaceships to perturb a glider. This can be done in a few different ways, but I still found nothing useful. Anyone else have better luck?

Finally, the block deleting feature of the spaceship allows us to construct a new type of growing spaceship. Here a c/3 period 24 block puffer has its output consumed by the c/5 spaceship. The line of blocks grows longer and longer:

My motivation for finding this spaceship is the realization that gliders can approach a c/5 ship from the back. This means that gliders don't have to react at the sides, but can react anywhere along the back edge. So instead of trying to find long and thin spaceships, it seems better to find short and wide ones. With enough of a grammar built up, some back edge might be found which will perturb an incoming glider correctly to produce another one (plus junk, probably).

By the way, my recent success in finding objects has come about because of a certain circumstance at work. I happen to have five Pentimum 150's available full time for at least the medium term, and so I can do five different searches at the same time! I have also fixed a long term bug in my lifesrc program in which cells to be ignored did the wrong thing for other generations.

BCNU, -dbell-

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