Ellison p4 HW emulator (where "HW" stands for heavyweight ) is a period-4 oscillator that was found by Scot Ellison in April 2010 . Numerous variants of this oscillator have been found, including some producing different types of sparks , as shown below.

Gallery
```
x = 20, y = 9, rule = B3/S23
11b2o$4bo3bo5bob2o$3bobo11bo$3bobo9b2o$2obobob8o2b3o$2obo12bo2bo$3bo
13b2o$3bobo4b2o$4b2o4b2o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Ellison p4 HW emulator hybrid as seen in the period-36 glider gun ,^{[1]} with one half resembling a more traditional heavyweight emulator (click above to open LifeViewer )RLE : here Plaintext : here

Blocked p4s
```
x = 23, y = 14, rule = B3/S23
11bo$4bo3bo5bo3bo$3bobo11bobo$3bobo11bobo$2obobob9obobob2o$2obo15bob2o
$3bo15bo$3bobo4bobo4bobo$4bobob3ob3obobo$2bobob2o7b2obobo$2b2o5b2ob2o
5b2o$10bobo$10bobo$11bo!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4-1 acting as a middleweight emulator , found by Adam P. Goucher on April 5, 2010 (click above to open LifeViewer )RLE : here Plaintext : here

```
x = 23, y = 11, rule = B3/S23
11bo$4bo3bo5bo3bo$3bobo11bobo$3bobo11bobo$2obobob9obobob2o$2obo15bob2o
$3bo15bo$3bobo4bobo4bobo$4b2o3bob2o4b2o$9bo$8b2o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Stator reduction of blocked p4-1, by Matthias Merzenich (click above to open LifeViewer )RLE : here Plaintext : here

```
x = 22, y = 8, rule = B3/S23
4bo3bo4bo3bo$3bobo10bobo$3bobo10bobo$2obobob8obobob2o$2obo14bob2o$3bo
14bo$3bobo4b2o4bobo$4b2o4b2o4b2o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4-2 acting as a lightweight emulator , by Adam P. Goucher (click above to open LifeViewer )RLE : here Plaintext : here

```
x = 19, y = 9, rule = B3/S23
11bo$4bo3bo4bob2o$3bobo10bo$3bobo8b2o$2obobob7o2b3o$2obo11bo2bo$3bo12b
2o$3bobo$4b2o3b3o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4-4, a middleweight emulator hybrid by Merzenich. Used in the p48 pi-heptomino hassler and the pi orbital . (click above to open LifeViewer )RLE : here Plaintext : here

```
x = 18, y = 10, rule = B3/S23
4bo3bo3bob2o$3bobo9bo$3bobo7b2o$2obobob6o2b3o$2obo10bo2bo$3bo11b2o$3bo
bo5bo$4b2o4b2o$10b2o$10bo!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4-5, a lightweight emulator hybrid by Merzenich. Also an uncommon example of a toad being used as an induction coil . (click above to open LifeViewer )RLE : here Plaintext : here

T-noses
```
x = 25, y = 11, rule = B3/S23
11b3o2$10bo3bo$4bo3bo7bo3bo$3bobo13bobo$3bobo13bobo$2obobob11obobob2o$
2obo17bob2o$3bo17bo$3bobo4b2ob2o4bobo$4b2o4b2ob2o4b2o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4 T-nose , by Adam P. Goucher (click above to open LifeViewer )RLE : here Plaintext : here

```
x = 21, y = 13, rule = B3/S23
11b3o2$10bo3bo$4bo3bo6bob2o$3bobo12bo$3bobo10b2o$2obobob9o2b3o$2obo13b
o2bo$3bo14b2o$3bobo4bobo$4b2o4b2obo$13bo$13b2o!
#C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]]
```

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Blocked p4 T-nose hybrid, by Merzenich (click above to open LifeViewer )RLE : here Plaintext : here

Notes
↑ Although a so-called "underweight spaceship " does not produce any sparks, the blocked p4-3 is sometimes referred to as an "underweight emulator" due to the shortening of the oscillator by an additional cell beyond the lightweight version. The three-dot spark has also been referred to as the "obobo" spark^{[2]} due to its RLE representation, in analogy to the obo spark .
References
External links