L-Systems¶

lsystem KochCurve {
  set compressSvg = false;
  set symbols axiom = F; // F - - F - - F;
  set iterations = 1;

  // normalize line length to have (result image will have always same size)
  interpret F as DrawForward(2 ^ -(currentIteration * 3 / 2) * 512);
  interpret + as TurnLeft(60);
  interpret - as TurnLeft(-60);

  rewrite F to F + F - - F + F;
}

process all with SvgRenderer;

lsystem HilbertCurve {
 set compressSvg = false;
  set symbols axiom = L;
  set iterations = 2;

  interpret F as DrawForward(8);
  interpret + as TurnLeft(90);
  interpret - as TurnLeft(-90);

  rewrite L to + R F - L F L - F R +;
  rewrite R to - L F + R F R + F L -;
}

process all with SvgRenderer;

lsystem Plant3 {

  set symbols axiom = F(0);
  set initialAngle = 90;
  set iterations = 1;
  set randomSeed = 0;
  set compressSvg = false;

  interpret F(x) as DrawForward(12, 1+x*2,
    darken(#00FF00, random(0 + 0.1*x, 0.3 + 0.05*x)));
  interpret + as TurnLeft(22 + random(-5, 5));
  interpret - as TurnLeft(-22 + random(-5, 5));
  interpret [ as StartBranch;
  interpret ] as EndBranch;

  rewrite F(x) to F(x+1) F(x+1) - [ - F(0) + F(0) + F(0) ] + [ + F(0) - F(0) - F(0) ];
}

process all with SvgRenderer;

lsystem Tree extends Branches {

  let d1 = 94.74;  // divergence angle 1
  let d2 = 132.63;  // divergence angle 2
  let angle = 18.95;  // branching angle
  let l = 1.109;  // length increase rate
  let w = 1.732;  // width increase rate

  set symbols axiom = /(45) F(100, 1) A;
  set iterations = 6;
  set initialAngle = 90;
  set tropismVector = {0, -1, 0};
  set tropismCoefficient = 0.15;
  set scale = 0.7;

  interpret F as DrawForward;
  interpret f as MoveForward;
  interpret & as Pitch(-angle);
  interpret / as Roll;

  rewrite A to
    F(50, w) [ C & F(50, 1) A ] /(d1)
    [ C & F(50, 1) A ] /(d2) [ C & F(50, 1) A ];
  rewrite F(length, width) to F(length * l, width * w);
  rewrite f(length) to F(length * w);
  rewrite C to f(-1) &(-90) f(1) &(90);  // correction

}

process all with SvgRenderer;

lsystem MengerSponge {

  set iterations = 3;
  set symbols axiom = F;

  interpret F as DrawForward(10, 10, #FFFFFF);
  interpret f as MoveForward(5);
  interpret + as Yaw(90);
  interpret - as Yaw(-90);
  interpret ^ as Pitch(90);
  interpret & as Pitch(-90);

  rewrite F to
    - f f + & f f ^ F F F +f+f- F F +f+f- F F +f+f- F
    -f+f+f^f F F &f&f^ F F &f&f^ F ^ ^ f f f & + f F F &f&f^ F
    ^ ^ f f f & + f F F &f&f^ F ^ ^ f f f & + f F f & f f ^ +
    + f f - f f f f f;
  rewrite f to f f f;
}

process all with ThreeJsRenderer;

lsystem SierpinskiTrangle {
  set compressSvg = false;
  set symbols axiom = F + F + F;
  set iterations = 1;

  interpret F f as MoveForward(2 ^ -currentIteration * 600);
  interpret + as TurnLeft(120);
  interpret - as TurnLeft(-120);
  interpret < as StartPolygon(0, 0);
  interpret . as RecordPolygonVertex;
  interpret > as EndPolygon;

  rewrite F to < . F . + F . > + f + f F;
  rewrite f to f f;
  rewrite < to nothing;
  rewrite . to nothing;
  rewrite > to nothing;
}

process all with SvgRenderer;

lsystem AsciiHexaGosperCurve {

  set symbols axiom = L;
  set iterations = 3;
  set scale = 2;

  rewrite L to L + R + + R - L - - L L - R +;
  rewrite R to - L + R R + + R + L - - L - R;

  interpret R L as DrawLine;
  interpret + as TurnLeft;
  interpret - as TurnRight;
}

process all with HexAsciiRenderer;