x = 47, y = 21, rule = B3678/S34678
23bo$$23bo$$23bo$$23bo$4boobboobboo6boo3boo6boobboobboo$3bobboobboobb
6obb3obb6obboobboobbo$b22ob22o$b45o$23ob23o$oobobboobboobb6obb3obb6obb
oobboobboboo$4boobboobboo6boo3boo6boobboobboo$23bo$$23bo$$23bo$$23bo!
A period 40 spark oscillator.
The central spark can become a two bit spark if the column is duplicated.
David I. Bell, May 1997
