One generation before a fleet, but one of the cells of a ship-tie is prevented from forming. The two extra cells can come from anywhere and do not have to be sparks. (click above to open LifeViewer) RLE:herePlaintext:here
All strict still lifes with a population of 21 or fewer cells, as well as all oscillators and spaceships with 16 or fewer cells, are known to be glider-constructible. A glider synthesis of this object can be found in the infobox to the right.