const xSimplexZoom = .01; //min=0.001 max=.5 step=0.001
const ySimplexZoom = .01; //min=0.001 max=.5 step=0.001
const magnitude = 6.5; //min=0 max=10 step=.1
const rings = 15; //min=1 max=50 step=1
const oddDeltaRadius = 10; //min=1 max=30 step=.5
const evenDeltaRadius = 10; //min=1 max=30 step=.5
const startHatched = 0; //min=0 max=1 step=1 (Yes, No)
const plotPenWidth = .15; //min=0 max=2 step=.01
const precision = 1;//min=.5 max=10 step=.5

// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(1);

// Global code will be evaluated once.
const turtle = new Turtle();
const polygons = new Polygons();
const noiseXY = [new SimplexNoise((Math.random() * 100) | 0), new SimplexNoise((Math.random() * 100) | 0)];

// The walk function will be called until it returns false.
function walk(i) {
    const r = Math.ceil((i + 1) / 2) * oddDeltaRadius //oddCircles
            + Math.ceil(i/2) * evenDeltaRadius; //evenCircles
    const pts = circlePoints(r - oddDeltaRadius /2).map(pt => warp(pt));
    
    const p = polygons.create();
    p.addPoints(...pts);
    if(plotPenWidth > 0 && i%2 == startHatched) p.addHatching(1, plotPenWidth);
    p.addOutline();
    polygons.draw(turtle, p);

    return i < rings - 1;
}

function warp(pt) { function add2(a, b) { return [a[0]+b[0], a[1]+b[1]]; }function scale2(a, s) { return [a[0]*s,a[1]*s]; }return add2(pt, scale2([noiseXY[0].noise2D(scale2(pt, xSimplexZoom)), noiseXY[1].noise2D(scale2(pt, ySimplexZoom))], magnitude));}
function circlePoints(radius, extend = 2 * Math.PI, clockWiseStart = 0, steps = null, includeLast = false) { return [steps == null? (radius*precision*extend+1)|0: steps].map(steps => Array.from({length: steps}).map((v, i, a) => [radius * Math.cos(clockWiseStart + extend*i/(a.length-(includeLast?1:0))), radius * Math.sin(clockWiseStart + extend*i/(a.length-(includeLast?1:0)))])).pop(); }

////////////////////////////////////////////////////////////////
// Polygon Clipping utility code - Created by Reinder Nijhoff 2019
// (Polygon binning by Lionel Lemarie 2021)
// https://turtletoy.net/turtle/a5befa1f8d
////////////////////////////////////////////////////////////////
function Polygons(){const t=[],s=25,e=Array.from({length:s**2},t=>[]),n=class{constructor(){this.cp=[],this.dp=[],this.aabb=[]}addPoints(...t){let s=1e5,e=-1e5,n=1e5,h=-1e5;(this.cp=[...this.cp,...t]).forEach(t=>{s=Math.min(s,t[0]),e=Math.max(e,t[0]),n=Math.min(n,t[1]),h=Math.max(h,t[1])}),this.aabb=[s,n,e,h]}addSegments(...t){t.forEach(t=>this.dp.push(t))}addOutline(){for(let t=0,s=this.cp.length;t<s;t++)this.dp.push(this.cp[t],this.cp[(t+1)%s])}draw(t){for(let s=0,e=this.dp.length;s<e;s+=2)t.jump(this.dp[s]),t.goto(this.dp[s+1])}addHatching(t,s){const e=new n;e.cp.push([-1e5,-1e5],[1e5,-1e5],[1e5,1e5],[-1e5,1e5]);const h=Math.sin(t)*s,o=Math.cos(t)*s,a=200*Math.sin(t),i=200*Math.cos(t);for(let t=.5;t<150/s;t++)e.dp.push([h*t+i,o*t-a],[h*t-i,o*t+a]),e.dp.push([-h*t+i,-o*t-a],[-h*t-i,-o*t+a]);e.boolean(this,!1),this.dp=[...this.dp,...e.dp]}inside(t){let s=0;for(let e=0,n=this.cp.length;e<n;e++)this.segment_intersect(t,[.1,-1e3],this.cp[e],this.cp[(e+1)%n])&&s++;return 1&s}boolean(t,s=!0){const e=[];for(let n=0,h=this.dp.length;n<h;n+=2){const h=this.dp[n],o=this.dp[n+1],a=[];for(let s=0,e=t.cp.length;s<e;s++){const n=this.segment_intersect(h,o,t.cp[s],t.cp[(s+1)%e]);!1!==n&&a.push(n)}if(0===a.length)s===!t.inside(h)&&e.push(h,o);else{a.push(h,o);const n=o[0]-h[0],i=o[1]-h[1];a.sort((t,s)=>(t[0]-h[0])*n+(t[1]-h[1])*i-(s[0]-h[0])*n-(s[1]-h[1])*i);for(let n=0;n<a.length-1;n++)(a[n][0]-a[n+1][0])**2+(a[n][1]-a[n+1][1])**2>=.001&&s===!t.inside([(a[n][0]+a[n+1][0])/2,(a[n][1]+a[n+1][1])/2])&&e.push(a[n],a[n+1])}}return(this.dp=e).length>0}segment_intersect(t,s,e,n){const h=(n[1]-e[1])*(s[0]-t[0])-(n[0]-e[0])*(s[1]-t[1]);if(0===h)return!1;const o=((n[0]-e[0])*(t[1]-e[1])-(n[1]-e[1])*(t[0]-e[0]))/h,a=((s[0]-t[0])*(t[1]-e[1])-(s[1]-t[1])*(t[0]-e[0]))/h;return o>=0&&o<=1&&a>=0&&a<=1&&[t[0]+o*(s[0]-t[0]),t[1]+o*(s[1]-t[1])]}};return{list:()=>t,create:()=>new n,draw:(n,h,o=!0)=>{reducedPolygonList=function(n){const h={},o=200/s;for(var a=0;a<s;a++){const c=a*o-100,r=[0,c,200,c+o];if(!(n[3]<r[1]||n[1]>r[3]))for(var i=0;i<s;i++){const c=i*o-100;r[0]=c,r[2]=c+o,n[0]>r[2]||n[2]<r[0]||e[i+a*s].forEach(s=>{const e=t[s];n[3]<e.aabb[1]||n[1]>e.aabb[3]||n[0]>e.aabb[2]||n[2]<e.aabb[0]||(h[s]=1)})}}return Array.from(Object.keys(h),s=>t[s])}(h.aabb);for(let t=0;t<reducedPolygonList.length&&h.boolean(reducedPolygonList[t]);t++);h.draw(n),o&&function(n){t.push(n);const h=t.length-1,o=200/s;e.forEach((t,e)=>{const a=e%s*o-100,i=(e/s|0)*o-100,c=[a,i,a+o,i+o];c[3]<n.aabb[1]||c[1]>n.aabb[3]||c[0]>n.aabb[2]||c[2]<n.aabb[0]||t.push(h)})}(h)}}}

////////////////////////////////////////////////////////////////
// Simplex Noise utility code. Created by Reinder Nijhoff 2020
// https://turtletoy.net/turtle/6e4e06d42e
// Based on: http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
////////////////////////////////////////////////////////////////
function SimplexNoise(seed = 1) {const grad = [  [1, 1, 0], [-1, 1, 0], [1, -1, 0], [-1, -1, 0],[1, 0, 1], [-1, 0, 1], [1, 0, -1], [-1, 0, -1],[0, 1, 1], [0, -1, 1], [0, 1, -1], [0, -1, -1] ];const perm = new Uint8Array(512);const F2 = (Math.sqrt(3) - 1) / 2, F3 = 1/3;const G2 = (3 - Math.sqrt(3)) / 6, G3 = 1/6;const dot2 = (a, b) => a[0] * b[0] + a[1] * b[1];const sub2 = (a, b) => [a[0] - b[0], a[1] - b[1]];const dot3 = (a, b) => a[0] * b[0] + a[1] * b[1] + a[2] * b[2];const sub3 = (a, b) => [a[0] - b[0], a[1] - b[1], a[2] - b[2]];class SimplexNoise {constructor(seed = 1) {for (let i = 0; i < 512; i++) {perm[i] = i & 255;}for (let i = 0; i < 255; i++) {const r = (seed = this.hash(i+seed)) % (256 - i)  + i;const swp = perm[i];perm[i + 256] = perm[i] = perm[r];perm[r + 256] = perm[r] = swp;}}noise2D(p) {const s = dot2(p, [F2, F2]);const c = [Math.floor(p[0] + s), Math.floor(p[1] + s)];const i = c[0] & 255, j = c[1] & 255;const t = dot2(c, [G2, G2]);const p0 = sub2(p, sub2(c, [t, t]));const o  = p0[0] > p0[1] ? [1, 0] : [0, 1];const p1 = sub2(sub2(p0, o), [-G2, -G2]);const p2 = sub2(p0, [1-2*G2, 1-2*G2]);let n =  Math.max(0, 0.5-dot2(p0, p0))**4 * dot2(grad[perm[i+perm[j]] % 12], p0);n += Math.max(0, 0.5-dot2(p1, p1))**4 * dot2(grad[perm[i+o[0]+perm[j+o[1]]] % 12], p1);n += Math.max(0, 0.5-dot2(p2, p2))**4 * dot2(grad[perm[i+1+perm[j+1]] % 12], p2);return 70 * n;}hash(i) {i = 1103515245 * ((i >> 1) ^ i);const h32 = 1103515245 * (i ^ (i>>3));return h32 ^ (h32 >> 16);}}return new SimplexNoise(seed);}