Switch engine ping-pong

Switch engine ping-pong
View static image
Pattern type	Breeder
Number of cells	23
Bounding box	210515 × 183739
Direction	Diagonal
Period	2326656
Speed	c/12
Discovered by	Michael Simkin
Year of discovery	2014
Glider synthesis Fewest gliders (canonical) 12 Fewest gliders (cheapest variant) 7
Pattern files RLE switchenginepingpong.rle

Switch engine ping-pong is a quadratic growth pattern that was found by Michael Simkin on October 29, 2014. In terms of its 23 cells it was formerly the smallest known quadratic growth pattern, superseding the previous record holder, 24-cell quadratic growth, also found by Simkin a week earlier, but having since been beaten out by 22-, 21-, and 20-cell patterns in 2022.

The initial state of the pattern contains a pre-block and a glider headed towards an R-pentomino grandparent in the top-left corner, and a glider headed towards an R-pentomino in the bottom-right. The R-pentomino and glider interactions create two parallel switch engines headed to the top-right, and a middleweight spaceship which collides with them repeatedly to form switch engines headed to the bottom-right, leading to quadratic growth.

It is the first such pattern found that uses only 2 switch engines, and it shows that quadratic growth can be synthesized with no more than 7 gliders.

Gallery

• 
  Generation 40,210,710,958,656, viewed at a scale of 2³⁶:1.
• 
  Generation 40,210,710,958,656, viewed at a scale of 2¹³:1; zooming in on the left corner of the "solid triangle" reveals that it is in fact made up of branching "lines".
• 
  Generation 40,210,710,958,656, viewed at a scale of 1:1; zooming in further on the leftmost "branching point" reveals the structure of the "lines".

External links

• Switch engine ping-pong at the Life Lexicon