A '''block pusher''' is a pattern emitting [[stream]]s of [[glider]]s which can repeatedly push a [[block]] further away. This can be used as part of a [[sliding block memory]].
A '''block pusher''' is a pattern emitting [[stream]]s of [[glider]]s which can repeatedly push a [[block]] further away. This can be used as part of a [[sliding block memory]].
In the following example constructed by [[Dean Hickerson]] in April 1991,<ref>{{cite web|url=https://www.conwaylife.com/ref/DRH/bp5.html|title=Block pusher 5|work=Dean Hickerson's Game of Life page|author=Dean Hickerson|accessdate=November 4, 2021}}</ref> a 3-glider [[salvo]] pushes a block 10 units southeast and sends back 2 gliders, which cause another salvo to be fired. The round trip time increases by an average of 80 generations each time. More specifically, for n>=0, a salvo hits the block in generation 40 n^2 + 760 n + a[n mod 3], where a[0]=426, and a[1]=a[2]=626.
In the following example constructed by [[Dean Hickerson]] in April 1991,<ref>{{cite web|url=https://conwaylife.com/ref/DRH/bp5.html|title=Block pusher 5|work=Dean Hickerson's Game of Life page|author=Dean Hickerson|accessdate=November 4, 2021}}</ref> a 3-glider [[salvo]] pushes a block 10 units southeast and sends back 2 gliders, which cause another salvo to be fired. The round trip time increases by an average of 80 generations each time. More specifically, for n>=0, a salvo hits the block in generation 40 n^2 + 760 n + a[n mod 3], where a[0]=426, and a[1]=a[2]=626.
In the following example constructed by Dean Hickerson in April 1991,[1] a 3-glider salvo pushes a block 10 units southeast and sends back 2 gliders, which cause another salvo to be fired. The round trip time increases by an average of 80 generations each time. More specifically, for n>=0, a salvo hits the block in generation 40 n^2 + 760 n + a[n mod 3], where a[0]=426, and a[1]=a[2]=626.