x = 35, y = 25, rule = B3678/S34678
17bo$$17bo$$17bo$$17bo$$17bo$12b4o3b4o$3b9o4b3o4b9o$b16ob16o$b33o$17ob
17o$oob9o4b3o4b9oboo$12b4o3b4o$17bo$$17bo$$17bo$$17bo$$17bo!
A period 30 spark oscillator.
The central spark can become a two-bit spark if the column is duplicated.
David I. Bell, May 1997
