User:Tropylium/Vessel

Vessels are a diagonally extensible family of strict still lifes. All vessels have a diagonal width of no more than 3 lanes. The basic structure is a series of diagonally connected pairs of cells.

The basic vessel is the four-cell tub, with two cell pairs. This can be lengthened to produce the barge (three pairs), long barge (four pairs), etc.

Adding a single additional cell at one end of a vessel produces the boat subfamily; adding cells at both ends produces the ship subfamily.

Boats and ships can be joined as single-point ties with each other or with other still lifes featuring a pre-block protrusion. Tubs/barges and boats can also be joined with each other as two-point ties, but this will only produce a longer vessel.

The block can be considered a degenerate ship of length 1, aside from the fact that it cannot be used in ties.