Generation of R pentomino

It is almost inevitable for a stable square herb pattern to form spontaneously. Alternatively, one can be generated. Once a square is generated, the PC needs to generate only one additional bush to form the R pentomino pattern, which grows explosively. Follow the steps shown below: 
 . = empty, no change    1) ...... 2) ...... 3) ...... 4) ...... 5) ...... 6) ......
 o = alive, boring          ......    ......    .+....    .kn...    ..o...    ..o...
 + = added by you           ..oo..    ..oo..    ..oo..    .noo..    .ooo..    .ooo..
 - = killed by you          ..oo..    ..o-..    ..o...    ..on..    ..-o..    ...o..
 n = generated by rules     ......    ......    ......    ......    ......    ......
 k = killed by rules
This pattern will then grow for dozens of generations.