Generate the outline of an island from a seed The challenge is to draw the outline of an 'island', generated using a seed as input.


Input (seed): string of 6 characters (exactly) allowing only lowercase letters (i.e. abcdefghijklmnopqrstuvwxyz) - examples: 'island', 'aaaaaa', 'jhgcfj'
Each seed is to give a unique island (i.e. no two seeds will give the same output)
No output is to be a transformation of another seed's output. That's translation, reflection, rotation, scaling or any combination thereof.
Using the same seed should always give the same output
Output: 600px by 600px image


A valid island is drawn using a single line, which:


forms a closed loop
is 1px thick with no smoothing, blurring etc. 
is continuous (i.e. after drawing a pixel the next pixel will be in one of the 8 adjoining spaces that isn't occupied)
does not cross itself at any point
does not leave the boundaries of the image
is black (#000), on a background of white (#FFF)
has no lines of reflective symmetry
must enclose white space


Source code has a limit of 500 bytes.

Aside from that, popularity decides; most votes wins.
BBC basic
Here's a very simple algorithm, which could be refined for more realism. If there are further changes in the rules I'm willing to change / delete.
take the 6 character string and add }@ to ensure asymmetry (this particular choice of characters gives islands that vaguely resemble Antarctica)
draw a line that connects 8 points at 45 degree intervals, with distance from the centre determined by the ASCII code.
  INPUT a$
  a$=a$+&quot;}@&quot;
  MOVE 364,300
  FOR i=1 TO 8
    r=4*ASC(MID$(a$,i))-192
    DRAW 300+r*COS(i*PI/4),300+r*SIN(i*PI/4)
  NEXT