#N elastic-growth.rle
#O dani, 2 March 2017
#C
#C Active blobs of whitespace with diagonal and horizontal boundaries
#C grow and shrink until a minor phase transition occurs around T=2000,
#C when a roughly diamond-shaped stable central core appears and begins
#C to grow steadily.
#C
#C Reference:
#C https://conwaylife.com/forums/viewtopic.php?p=41111#p41111
#C
#C See also rules with fluxional "amoebas": 
#C https://conwaylife.com/forums/viewtopic.php?p=94257#p94257
x = 4, y = 3, rule = B2-a5678/S125678
obo$bo$3bo!