In his continuing quest for Diagonal Spaceships, Nicolay Beluchenko has also found what is currently the smallest known "Grow-By-One" pattern. This type of pattern is one whose population growth rate is exactly linear, without any fluctuations, adding a single bit every generation. Shown here is a slight improvement by David Bell, which starts a generation earlier than Beluchenko's orginal pattern, with a population of 44 at generation 0. (The purpose of the Lightweight Spaceship is to smooth out the fluctuations in the paired wickstretcher's population.)
On June 24th, David Bell produced an optimized version of Jason Summers' original lineship (shown in reduced scale at right -- click the thumbnail for the RLE, or here for a full picture). There have been several further developments along these lines.
dgreene used some of David Bell's new compact Cordership technology to produce a modified tail section for the revised lineship which repeats at p768 instead of at p96.
[The thumbnail at right shows only the modified tail section -- click here for a picture of the full pattern.]
David Bell followed this with a redesigned diagonal c/12 period 96 lineship. In this variant, the creation of the line at the front is done in pieces which are then welded together to form the line, using the repair techniques described in the "Cutting and Repairing Diagonal Lines" posting. The back end has also been reduced, since a sideways rake is not needed to ignite the line.
Again, only the smaller back end is shown in the thumbnail; a full-sized image is here.
The Cordership at the tail end of the adjustable-period lineship shown at right (full-sized image here) is responsible for igniting the stabilized end of line whenever it gets near to it. Nicolay Beluchenko points out that this Cordership could be adjusted by moving the trailing Cordership by multiples of 22 cells diagonally, rather than 88, if the front of the line were constructed in length-22 segments as well (but this would make the front of the ship much larger).
Hartmut Holzwart has constructed several new 2c/4 greyships (spaceships consisting primarily of alternating lines of ON and OFF cells -- see this previous post.) Here are two versions of a 2c/4 perpendicular greyship, in which the direction of travel is perpendicular to the alternating stripes, instead of parallel to them:
It's possible to shorten an arm of one of the above ships to get a triangle, as shown at right. Some further incomplete perpendicular-greyship results can be found here. Another triangle that uses some of these connections is shown at the far right.
On July 2, David Bell noticed that tub-with-tails are larger than needed to form switch-engine lanes (see the bobsled-run posting on 24 June 2005). Several smaller still lifes with tub-shaped protrusions can provide the same catalysis; boats, barges, long boats, long barges, etc. can all be used. At right is a revised switch-engine 'bobsled run' using boats as catalysts.
Long barges can be used as a common boundary between two adjacent lanes without any possible interference. Barges are sufficient if traffic in adjacent lanes is in opposite directions, or if the timing of traffic in two parallel lanes can be controlled to avoid mirror-image switch-engine phases. At right is a p3450 'swimmer' -- a switch engine doing laps in a lane made of boats: