a frosty fractal

frosty.r

par(mfrow=c(1,1))
par(mar=c(0,0,0,0))
l=1.2
# variables
res=1000
n=500
x <- y <- seq(-l,l, length.out=res)
c <- outer(x,y*1i,FUN="+")
z <- matrix(0.0, nrow=res, ncol=res)
o <- matrix(1e5, nrow=res, ncol=res)
index <- which(Mod(z) < 5)
o[index] <- pmin(o[index] , abs(1-Mod(z[index])))

 for (rep in 1:20) { 
   #print(rep)
   index <- which(Mod(z) < 5)
   z[index] <- 
     1*z[index]^(7) +
     1*c[index]
    z[index] <- 
      z[index]^(13)+
      1*c[index]
    }
z=z^3*1
for (rep in 1:n) { 
  z[index] <- (z[index]^2)-(0.48-.62i)
  o[index] <- pmin(o[index] , abs(Mod((z[index]))))
}
o2 <- -log(o) 
o2 <- (o2 - min(o2)) / (max(o2)-min(o2))
pal=sample(hcl.pals(),1)
print(pal)
image(x,y,pmax(o2^1.1,0),
      col=hcl.colors(pal="Broc",1000, rev=F
                     ),
      asp=1,axes=F,ann=F,useRaster=TRUE)