Camelship
Camelship  
View static image  
Pattern type  Spaceship  

Number of cells  239822  
Bounding box  976094×976223  
Direction  Oblique  
Slope  3  
Period  3948264  
Mod  3948264  
Speed  (3,1)c/3948264  
Speed (unsimplified)  (3,1)c/3948264  
Heat  Unknown  
Discovered by  Chris Cain  
Year of discovery  2018  
 
 

 For the general concept of camelships as slope 3 spaceships, see Oblique spaceship.
On December 7, 2018, Chris Cain created a selfconstructing camelship spaceship, the first known spaceship with the minimum possible step size of (3,1).^{[1]} It was also considerably smaller than the Gemini 3, the only other known spaceship with a (3N, N) direction of travel.
Design
The camelship's design is roughly based on a volatility1 oscillator constructed the previous month.
The volatility1 oscillator's two halves are rotationally symmetric, which allows it to reuse the same destruction and reconstruction recipes on both sides of its loop. By contrast, the camelship needs two separate singlechannel recipes. The first recipe shoots down the circuitry on the left side and rebuilds it at an offset of (3, 1). If this recipe were reflected 180 degrees and used to shift the rightside circuitry, it would have the effect of moving it by (3, 1) instead of (3, 1) and the loop would no longer line up correctly.
Instead, the second recipe (which is inactive on the left side due to the first recipe constructing an eater on the construction arm lane) is activated on the right side by a glider that crosses the entire camelship on every cycle. This glider is produced by the leading gliders in the first recipe in the course of shifting a marker block by (3, 1) near the north corner. The glider interrupts the copied recipe along the southeast side, exactly at the transition point between the first and second recipes.
So at the east corner, the first recipe is absorbed by an eater (moose antlers) and the second recipe is activated to shift the rightside circuitry by (3, 1).
Application to other speeds
A similar method could be adapted to shift circuitry by any chosen distance, to make spaceships with other small step sizes, including oblique directions: giraffeship, ibisship, zebraship, antelopeship, etc. The recipes involving the eaters in the east and west corners and the block near the north corner would have to be reinvented or adjusted for each new step, but much of the other circuitry could remain the same. The only exception is that for any step (X, Y) where X+Y is odd, the reflecting circuitry on the right side must be different from the circuitry on the left, because the singlechannel recipes in such a spaceship will travel on alternate colours in successive cycles.
See also
References
 ↑ Chris Cain (December 7, 2018). Re: SelfConstructing Spaceship Challenges (discussion thread) at the ConwayLife.com forums
 Patterns
 Periodic objects with minimum population 1000 or more
 Patterns with 1000 or more cells
 Patterns found by Chris Cain
 Patterns found in 2018
 Patterns that can be constructed with 101 or more gliders
 Spaceships
 Spaceships with period 3948264
 Oblique spaceships
 Spaceships with slope 3
 Spaceships with speed (3,1)c/3948264
 Spaceships with unsimplified speed (3,1)c/3948264
 Spaceships with mod 3948264
 Adjustable spaceships