Today's post uses a formula using a Julia iteration loop producing
a spirals of threads design. Ready made at http://maxitersfractalfollies.blogspot.com


 Spirals of Threads      { ;  fract492.gif
                     ; blank
                     ; calctime   0:06:08.77
                     ; created Nov 02, 2010
                     ;  Fractint Version 2004 Patchlevel 10
  reset=2004 type=formula formulafile=kerrym.frm formulaname=km_10
  center-mag=-0.550248/0.349382/6.884776
  params=0.1263771477401044/0.1877803888058107/-0.8391064180425428/0.67070\
  52827539903/0.1497543259987182/0.7999206518753624/-0.749626148258919/0.7\
  06839197973571 float=y maxiter=1500 inside=0 decomp=256
  periodicity=0
  colors=000000000000000000000000000000000100100200400500700900B00D00G00I0\
  0L00O10Q10T10W10Z10a10e10h20k20o20r20v20y20z30z50z60z80z90zB0zC0zE0zF0zH\
  0zI0zK0zL0zN0zO0zQ0zR0zT0zU0zW0zX0zZ0z_0za0zb0zd0ze0zg0zh0zj0zk0zm0zn0zp\
  0zq0zs0zt0zv0zw0zy0zz1zz3zz4zz6zz7zz7zy7zx7zx7zw7zv7zv7zu7yt7ys7ys7yr7yq\
  6yq6yp6yo6yo6xn6xm6xl6xl6xk6xj6xj6xi5xh5wh5wg5wf5we5we5wd5wc5wc5vb5va5va\
  5v`4v_4vZ4vZ4vY4vX4uX4uW4uV4uV4uU4uT4uS3uS3uR3tQ3tQ3tP3tO3tO3tN3tM3tL3sL\
  3sK3sJ2sJ2sI2sH2sH2sG2sF2rE2rE2rD2rC2rC2rB1rA1rA1r91q81q71q71q61q51q51q4\
  1q31p20p20o20n20m20m20l20k20j20j20i20h20g20g20f20e20d20d20c20b20a20a20`2\
  0_20Z20Z20Y20X20W20W20V20U20T20T20S20R20Q20Q20P20O20N20N20M20L20K20K20J2\
  0I20H20H20G20F20E20E20E20D20D20C20C20C20B20B20A20A20A2092092092082082072\
  0720720620620520520520420420420320320220220220120120010
  }

frm: km_10  { ; Kerry Mitchell 11may98
        ; originally conic-near_juli
        ; tweaked so user can directly input
        ; julia parameters (p4) originally hardcoded
        ; to 0,1
        cc=p4, zc=pixel, maxr=1e12, minr=maxr, iter=1
        a=real(p1), b=imag(p1), c=real(p2), d=imag(p2)
        e=real(p3), f=imag(p3):
        iter=iter+1, zc=sqr(zc)+cc, x=real(zc), y=imag(zc)
        conic=|x*(a*x+b)+y*(c*y+d)+e*x*y+f|
        if (conic<minr)
          minr=conic
          end if
        if ((|zc|>maxr)||(iter==maxit))
          iter=-1
          t=log(minr)
          z=cos(t)+flip(sin(t))
          end if
        iter>0
        }
Roger Alexander