|View static image|
|Number of cells||182|
|Bounding box||59 × 57|
|Discovered by||Bill Gosper|
|Year of discovery||1997|
A finite pattern is total aperiodic if it evolves in such a way that no cell in the plane is eventually periodic.
The first example was found by Bill Gosper on November 16, 1997. A few days later, on November 19, he found the much smaller example that consists of three copies of backrake 2 (by David Buckingham), shown in the infobox. Two of the rakes release southwestbound gliders, which perform 90-degree kickbacks to the northwestbound outputs from the third rake. As each kickback happens farther away from the last one and shifts the central glider by one half-diagonal southwestwards, any cell in the plane will be covered by infinitely many gliders on their aperiodic lanes.
On June 24, 2004, Gosper found that a block can be added to the pattern to make the total periodic pattern shown below, in which every cell eventually becomes periodic (specifically period-1 vacuum, albeit incredibly slowly). The block remains untouched for about 363 generations. It deletes its nth glider (and is shifted) at about generation 357.5+5.5n.
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RLE: here Plaintext: here
A space nonfiller is also capable of touching every cell in the plane at least once and making them eventually OFF (period-1 vacuum)