Placing two nuclei side by side is a form of constraint. Separated by the width of a single cell they can be packed rather arbitrarily into a square lattice, for which an overall constraint is still necessary. (Such an arrangement is shown at Agar#Tile_agars.) The interiors of nuclei separated by the width of two cells are still protected, but the nuclei act like spark coils. Glasses constitutes a binary instance of the arrangement, which can be elaborated as much as desired within a square lattice. The overall figure has period 2, but the relation between the interior and exterior phase must be respected. Boundary constraint is still required. Incommensurability of the widths would preclude mixing single and double spacing except along a linear chain which could even be bounded by spark coils.
The scrubber appears commonly in random soups on a 6×6 torus. The walls stabilize each other; no casing is needed.
On 2021-06-25, Jim Hortons discovered in a D8_1 soup a period-8 oscillator, the blocktopus, in the centre of which both phases of a scrubber appear consecutively before vanishing.
monomerisation of Charity's scrubber-hassling p6 (click above to open LifeViewer) Catagolue: here
On 2022-02-11, Charity Engine discovered a C4_1 period-4 oscillator that contains the scrubber's rotor (and stator on alternate phases, but removes four cells a knight move away from its centre on phases in which the rotor cells are on).
a period-4 oscillator stabilising the scrubber's rotor in a periodic manner (click above to open LifeViewer) Catagolue: here
Oscillators containing partial scrubbers
The rotor of each quadrant of the pulsar in one phase closely resembles the scrubber, with only two cells adjacent to a corner missing.
Scrubber half stabilisations
Two halves (cut orthogonally, but including the central column of cells, with the rotor in the on phase), facing each other with a 3-cell gap, can be stabilised periodically by halves of the cwoozy, in a similar manner to xp3_4aab8oz69fwgz255d11.
Single half-scrubbers can also be supported in period 6 by sombrero variants (that do not only have their stators optimised given their tessellation, but to suppress scrubber nucleus edge births).
The scrubber's nucleus is a member of the set of four 5×5 oscillator partials that can be stabilised by gutter symmetry,[3] of which two other ones (that are asymmetric, so can be immersed only in toruses with a minimum size of 12×12) resemble it (and in one phase are equivalent to the scrubber missing two and one cell respectively), and also function as wicks.
A period-12 wick of glide-symmetric nuclei (click above to open LifeViewer)
The former of these (with a central gap of 2 cells to stabilise with spark coils instead of gutters, like glasses) can be stabilised with fenceposts from a seminatural oscillator.[4]
The scrubber can exhibit at least eight different evolution sequences across certain non-totalistic rules, allowing it to have any period between 1 and 8 inclusive.[5]
