const show = 1; //min=0 max=6 step=1 (None,Index,Offset,Cube,Double,Ring,Decoration)
const decoration = 0; //min=0 max=4 step=1 (Circle,Mini border,Scaled borders,Random fillers,Path truchet)
const loopMode = 0; //min=0 max=1 step=1 (Spiral - only affects index,Ring - only affects index)
const drawEdges = 1; //min=0 max=1 step=1 (False,True)
const edgeSize = 10; //min=2 max=30 step=1
const orientation = 0; //min=0 max=360 step=1
const rings = 5; //min=0 max=30 step=1
const clockwise = 0; //min=0 max=1 step=1 (False,True)

// 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 text = new Text();
const polygons = new Polygons();
turtle.radians();

const rotation = (orientation / 180) * Math.PI;
const clockwiseIndex = clockwise == 1;

turtle.seth(rotation);

class HexGrid {
    innerRVectors = []; // list of downright, upright, up, upleft, downleft, down vectors
    offsetModifiers = [
        [ 1, (column) => column % 2 == 0? 0: 1 ], // downright
        [ 1, (column) => column % 2 == 0? -1: 0 ], //upright
        [ 0, (column) => -1 ], //up 
        [-1, (column) => column % 2 == 0? -1: 0 ], //upleft
        [-1, (column) => column % 2 == 0? 0: 1 ], //downleft
        [ 0, (column) => 1 ] //down
    ];

    cubeModifiers = [[1,0,-1],[1,-1, 0],[0,-1,1],[-1,0,1],[-1,1,0],[0,1,-1]];
    
    iterator = null;
    
    currentOffset = [0,0];
    currentIndex = 0;
    currentCube = [0,0,0];
    currentDouble = [0,0];
    currentRing = 0;
    
    constructor(edgeSize, spiral = false, rotation = 0, clockwise = false) {
        this.edgeSize = edgeSize;
        this.innerSize = Math.sqrt(.75) * edgeSize;
        this.spiral = spiral;
        this.rotation = rotation;
        this.clockwise = clockwise
    }
    setInnerRVectors() {
        for(let i = 1; i <= 6; i++) {
            this.innerRVectors.push(trans2(rot2(((Math.PI / 3) * i * (this.clockwise? -1: 1)) - this.rotation), [0, this.innerSize * 2]));
        }
    }
    updateCoordination(index) {
        this.currentOffset = add2(this.currentOffset, [this.offsetModifiers[index][0], this.offsetModifiers[index][1](this.currentOffset[0])]);
        this.currentDouble = [this.currentOffset[0], this.currentOffset[1] + this.currentOffset[1] + (this.currentOffset[0] % 2 == 0? 0:1)];
        this.currentCube = add3(this.currentCube, this.cubeModifiers[index]);
        this.currentIndex++;
    }
    *spiralCellPositions() {
        let position = turtle.pos();

        yield this.yieldCell(position);
        while(this.currentRing++ !== false) {
            position = add2(position, this.innerRVectors[5]);
            this.updateCoordination(5);
            yield this.yieldCell(position);
            
            for(let j = 0; j < 6; j++) {
                for(let i = 0; i < this.currentRing - (j == 0? 1: 0); i++) {
                    position = add2(position, this.innerRVectors[j]);

                    this.updateCoordination(j);

                    yield this.yieldCell(position);
                }
            }
        }
    }
    *ringCellPositions() {
        let position = turtle.pos();
        
        yield this.yieldCell(position);
        while(this.currentRing++ !== false) {
            let rPosition = add2(position, scale2(this.innerRVectors[5], this.currentRing));

            this.currentOffset = [0, this.currentRing];
            this.currentDouble = [this.currentOffset[0], this.currentOffset[1] + this.currentOffset[1] + (this.currentOffset[0] % 2 == 0? 0:1)];
            this.currentCube = [0, this.currentRing, -this.currentRing];
            this.currentIndex++;

            yield this.yieldCell(rPosition);
            for(let i = 1; i <= 6; i++) {
                for(let n = 0; n < (i == 6? this.currentRing - 1: this.currentRing); n++) {
                    rPosition = add2(rPosition, this.innerRVectors[i % 6]);
                    this.updateCoordination(i % 6);
                    yield this.yieldCell(rPosition);
                }
            }
        }
    }
    yieldCell(position) {
        return new HexCell(this.edgeSize, position, this.currentIndex, this.currentOffset, this.currentCube, this.currentDouble, this.currentRing, this.rotation);
    }
    nextCell() {
        if(this.iterator == null) {
            this.setInnerRVectors();
            this.iterator = this.spiral? this.spiralCellPositions(): this.ringCellPositions();
            this.index = 0;
        }
        return this.iterator.next().value;
    }
}

class HexCell {
    constructor(size, position, index, offset, cube, double, ring, rotation) {
        this.position = position;
        this.index = index;
        this.offset = offset;
        this.cube = cube;
        this.double = double;
        this.ring = ring;
        this.size = size;
        this.rotation = rotation;
    }
    getBorderPoints(turtle, borderSize = null) {
        let isDown = turtle.isdown();
        turtle.up();

        if(borderSize == null) {
            borderSize = this.size;
        }

        turtle.forward(borderSize);
        turtle.right(turtle._fullCircle / 3);

        let points = [];
        for(let i = 0; i < 6; i++) {
            points.push(turtle.pos());
            turtle.forward(borderSize);
            turtle.right(turtle._fullCircle / 6);
        }

        turtle.left(turtle._fullCircle / 3);
        turtle.forward(-borderSize);

        if(isDown) { turtle.down(); }

        return points;
    }
    drawBorder(turtle, borderSize = null) {
        let points = this.getBorderPoints(turtle, borderSize);
        turtle.jump(points[0]);
        for(let i = 1; i < points.length; i++) {
            turtle.goto(points[i]);
        }
        turtle.goto(points[0]);
        turtle.jump(this.position);
    }
    write(turtle, mode) {
        let fontSize = 1;
        let txt = '';
        switch(mode) {
            case 1: //index
                fontSize = this.size / 45;
                txt = '' + this.index;
                break;
            case 2: //offset
                txt = '['+this.offset+']';
                fontSize = this.size / 90;
                break;
            case 3: //cube
                fontSize = this.size / 100;
                break;
            case 4: //double
                txt = '['+this.double+']';
                fontSize = this.size / 90;
                break;
            case 5: //ring
                fontSize = this.size / 45;
                txt = '' + this.ring;
                break;
        }
        let h = turtle.h();
        turtle.up()
        
        if(mode == 3) {
            let pos = turtle.pos();
            for(let i = 0; i < 3; i++) {
                turtle.left(Math.PI / 2);
                turtle.forward((this.size / 1.8));
                turtle.right(Math.PI / 2);
                txt = ''+this.cube[i];
                let hh = turtle.h();
                turtle.seth(0);
                turtle.backward(txt.length * 10 * fontSize);
                text.print(turtle, txt, fontSize);
                turtle.seth(hh);
                turtle.up()
                turtle.jump(pos);
                turtle.right((2 * Math.PI) / 3);
            }
            turtle.down()
        } else {
            turtle.seth(0);
            turtle.backward(txt.length * 10 * fontSize);
            turtle.down();
            text.print(turtle, txt, fontSize);
        }
        
        turtle.seth(h);
    }
    decorate(turtle, mode) {
        switch(mode) {
            case 0: //circle
                let h = turtle.h();
                turtle.seth(0);
                turtle.jump(this.position[0], this.position[1] - (this.size / 2));
                turtle.circle(this.size / 2);
                turtle.seth(h);
                break;
            case 1: //mini border
                this.drawBorder(turtle, this.size * .8);
                break;
            case 2:
                for(let i = .8; i > 0; i -= .2) {
                    this.drawBorder(turtle, this.size * i);
                }
                break;
            case 3: //random fill
                let points = this.getBorderPoints(turtle);

                let p = polygons.create();
                p.addPoints(...points);
                p.addHatching(Math.random() * 360, (Math.random() * 1.5) + .2);
                polygons.draw(turtle, p, true);

                break;
            case 4: //path truchet
                drawReinderHexagon(turtle, this.position[0], this.position[1], this.size, .28, this.rotation);
                break;
        }
    }
}

let hg = new HexGrid(edgeSize, loopMode === 0, rotation, clockwiseIndex);

// The walk function will be called until it returns false.
function walk(i) {
    let cell = hg.nextCell();
    turtle.jump(cell.position);
    if(drawEdges) {
        cell.drawBorder(turtle);
    }
    
    switch(show) {
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
            cell.write(turtle, show);
            break;
        case 6:
            cell.decorate(turtle, decoration);
        default:
    }

    return i < (nthTriangular(rings) * 6);
}

function nthTriangular(n) { return ((n * n) + n) / 2; }

// 
// Vector math
//

function rot2(a) { return [Math.cos(a), -Math.sin(a), Math.sin(a), Math.cos(a)]; }
function trans2(m, a) { return [m[0]*a[0]+m[2]*a[1], m[1]*a[0]+m[3]*a[1]]; }
function scale2(a,b) { return [a[0]*b,a[1]*b]; }
function add2(a,b) { return [a[0]+b[0],a[1]+b[1]]; }
function add3(a,b) { return [a[0]+b[0],a[1]+b[1],a[2]+b[2]]; }


////////////////////////////////////////////////////////////////
// Text utility code. Created by Reinder Nijhoff 2019
// https://turtletoy.net/turtle/1713ddbe99
// Jurgen 2021: Fixed Text.print() to restore turtle._fullCircle
//.             if was in e.g. degrees mode (or any other)
////////////////////////////////////////////////////////////////
function Text() {class Text {print (t, str, scale = 1, italic = 0, kerning = 1) {let fc = t._fullCircle;t.radians();let pos = [t.x(), t.y()], h = t.h(), o = pos;str.split('').map(c => {const i = c.charCodeAt(0) - 32;if (i < 0 ) {pos = o = this.rotAdd([0, 48*scale], o, h);} else if (i > 96 ) {pos = this.rotAdd([16*scale, 0], o, h);} else {const d = dat[i], lt = d[0]*scale, rt = d[1]*scale, paths = d[2];paths.map( p => {t.up();p.map( s=> {t.goto(this.rotAdd([(s[0]-s[1]*italic)*scale - lt, s[1]*scale], pos, h));t.down();});});pos = this.rotAdd([(rt - lt)*kerning, 0], pos, h);}});t._fullCircle = fc;}rotAdd (a, b, h) {return [Math.cos(h)*a[0] - Math.sin(h)*a[1] + b[0], Math.cos(h)*a[1] + Math.sin(h)*a[0] + b[1]];}}const dat = ('br>eoj^jl<jqirjskrjq>brf^fe<n^ne>`ukZdz<qZjz<dgrg<cmqm>`thZhw<lZlw<qao_l^h^e_caccdeefggmiojpkqmqporlshsercp>^vs^as<f^h`hbgdeeceacaab_d^f^h_k`n`q_s^<olmmlolqnspsrrspsnqlol>]wtgtfsereqfphnmlpjrhsdsbraq`o`makbjifjekckaj_h^f_eaecffhimporqssstrtq>eoj`i_j^k_kajcid>cqnZl\\j_hcghglhqjulxnz>cqfZh\\j_lcmhmllqjuhxfz>brjdjp<egom<ogem>]wjajs<ajsj>fnkojpiojnkokqis>]wajsj>fnjniojpkojn>_usZaz>`ti^f_dbcgcjdofrisksnrpoqjqgpbn_k^i^>`tfbhak^ks>`tdcdbe`f_h^l^n_o`pbpdofmicsqs>`te^p^jfmfogphqkqmppnrkshserdqco>`tm^clrl<m^ms>`to^e^dgefhekenfphqkqmppnrkshserdqco>`tpao_l^j^g_ebdgdlepgrjsksnrppqmqlpingkfjfggeidl>`tq^gs<c^q^>`th^e_dadceegfkgnhpjqlqopqorlshserdqcocldjfhigmfoepcpao_l^h^>`tpeohmjjkikfjdhcecddaf_i^j^m_oapepjoomrjshserdp>fnjgihjikhjg<jniojpkojn>fnjgihjikhjg<kojpiojnkokqis>^vrabjrs>]wagsg<amsm>^vbarjbs>asdcdbe`f_h^l^n_o`pbpdofngjijl<jqirjskrjq>]xofndlcicgdfeehekfmhnknmmnk<icgefhfkgmhn<ocnknmpnrntluiugtdsbq`o_l^i^f_d`bbad`g`jambodqfrislsorqqrp<pcokompn>asj^bs<j^rs<elol>_tc^cs<c^l^o_p`qbqdpfoglh<chlhoipjqlqopqorlscs>`urcqao_m^i^g_eadccfckdnepgrismsorqprn>_tc^cs<c^j^m_oapcqfqkpnopmrjscs>`sd^ds<d^q^<dhlh<dsqs>`rd^ds<d^q^<dhlh>`urcqao_m^i^g_eadccfckdnepgrismsorqprnrk<mkrk>_uc^cs<q^qs<chqh>fnj^js>brn^nnmqlrjshsfreqdndl>_tc^cs<q^cl<hgqs>`qd^ds<dsps>^vb^bs<b^js<r^js<r^rs>_uc^cs<c^qs<q^qs>_uh^f_daccbfbkcndpfrhslsnrppqnrkrfqcpan_l^h^>_tc^cs<c^l^o_p`qbqepgohlici>_uh^f_daccbfbkcndpfrhslsnrppqnrkrfqcpan_l^h^<koqu>_tc^cs<c^l^o_p`qbqdpfoglhch<jhqs>`tqao_l^h^e_caccdeefggmiojpkqmqporlshsercp>brj^js<c^q^>_uc^cmdpfrisksnrppqmq^>asb^js<r^js>^v`^es<j^es<j^os<t^os>`tc^qs<q^cs>asb^jhjs<r^jh>`tq^cs<c^q^<csqs>cqgZgz<hZhz<gZnZ<gznz>cqc^qv>cqlZlz<mZmz<fZmZ<fzmz>brj\\bj<j\\rj>asazsz>fnkcieigjhkgjfig>atpeps<phnfleiegfehdkdmepgrislsnrpp>`sd^ds<dhffhekemfohpkpmopmrkshsfrdp>asphnfleiegfehdkdmepgrislsnrpp>atp^ps<phnfleiegfehdkdmepgrislsnrpp>asdkpkpiognfleiegfehdkdmepgrislsnrpp>eqo^m^k_jbjs<gene>atpepuoxnylzizgy<phnfleiegfehdkdmepgrislsnrpp>ate^es<eihfjemeofpips>fni^j_k^j]i^<jejs>eoj^k_l^k]j^<kekvjyhzfz>are^es<oeeo<ikps>fnj^js>[y_e_s<_ibfdegeifjijs<jimfoeretfuius>ateees<eihfjemeofpips>atiegfehdkdmepgrislsnrppqmqkphnfleie>`sdedz<dhffhekemfohpkpmopmrkshsfrdp>atpepz<phnfleiegfehdkdmepgrislsnrpp>cpgegs<gkhhjfleoe>bsphofleieffehfjhkmlompopporlsisfrep>eqj^jokrmsos<gene>ateeeofrhsksmrpo<peps>brdejs<pejs>_ubefs<jefs<jens<rens>bseeps<pees>brdejs<pejshwfydzcz>bspees<eepe<esps>cqlZj[i\\h^h`ibjckekgii<j[i]i_jakbldlfkhgjkllnlpkrjsiuiwjy<ikkmkojqirhthvixjylz>fnjZjz>cqhZj[k\\l^l`kbjcieigki<j[k]k_jaibhdhfihmjilhnhpirjskukwjy<kkimiojqkrltlvkxjyhz>^vamakbhdgfghhlknlplrksi<akbidhfhhillnmpmrlsisg>brb^bscsc^d^dsese^f^fsgsg^h^hsisi^j^jsksk^l^lsmsm^n^nsoso^p^psqsq^r^rs').split('>').map(r=> { return [r.charCodeAt(0)-106,r.charCodeAt(1)-106, r.substr(2).split('<').map(a => {const ret = []; for (let i=0; i<a.length; i+=2) {ret.push(a.substr(i, 2).split('').map(b => b.charCodeAt(0)-106));} return ret; })]; });return new Text();}

////////////////////////////////////////////////////////////////
// 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)}}}

// Reinder's truchet fill from https://turtletoy.net/turtle/e5df5b10e0
function drawReinderHexagon(t, x, y, scale, lineWidth, rotation) {
//    if (Math.abs(scale*x) > 100+scale ||
//        Math.abs(scale*y) > 100+scale) return; // early discard
        
    const h0 = Math.sqrt(3)/2;
    const h1 = 1/2;

    const a = ((Math.random()*3)|0)*Math.PI/3; // random angle
    const poly = new Polygons();
    
    // 2 transform functions: translate-scale (for background hatching), and rotate-translate-scale
    const ts  = p => [(scale*p[0])+x,(scale*p[1])+y];
    const rts = p => ts([Math.cos(a)*p[0]+Math.sin(a)*p[1], Math.cos(a)*p[1]-Math.sin(a)*p[0]]);

    // vec2 helper functions
    const add = (a, b) => [a[0]+b[0], a[1]+b[1]];
    const sub = (a, b) => [a[0]-b[0], a[1]-b[1]];
    const scl = (a, b) => [a[0]*b, a[1]*b];
    
    const rm = [Math.cos(-rotation), -Math.sin(-rotation), Math.sin(-rotation), Math.cos(-rotation)];
    const rotate = (a) => [rm[0]*a[0]+rm[2]*a[1], rm[1]*a[0]+rm[3]*a[1]];

    // 2 methods to create lines in a tile
    const line = (s, e, d) => { // line from s to e and width d
        const p = poly.create();
        p.addPoints(rts(add(s,d)), rts(add(e,d)), rts(sub(e,d)), rts(sub(s,d)));
        p.addSegments(rts(add(s,d)), rts(add(e,d)), rts(sub(e,d)), rts(sub(s,d)));
        return p;
    }
    const circle = (c, r, s, e) => { // circle around c, from angle s to e with radius r
        const p = poly.create(), c0 =[], c1 = [], f=10;
        for (let i=0; i<=f; i++) {
            c0.push(rts(add(c, [Math.cos(s+(e-s)*i/f)*(r+lineWidth), Math.sin(s+(e-s)*i/f)*(r+lineWidth)])));
            c1.push(rts(add(c, [Math.cos(e-(e-s)*i/f)*(r-lineWidth), Math.sin(e-(e-s)*i/f)*(r-lineWidth)])));
        }
        p.addPoints(...c0,...c1);
        for (let i=0; i<f; i++) p.addSegments(c0[i], c0[i+1]);
        for (let i=0; i<f; i++) p.addSegments(c1[i], c1[i+1]);
        return p;
    }
    
    // six corners of hexagon
    const c = [];
    for (let i=0; i<6; i++) {
        c.push([Math.cos((i*Math.PI/3) + rotation), Math.sin((i*Math.PI/3) + rotation)]);
    }
    
    // generate lines in tile
    const l = [], tileType = (Math.random()*5)|0; // 5 different tile types
    
    switch (tileType) {
        case 0:  l.push(line(rotate([0,h0]), rotate([0,-h0]), rotate([lineWidth, 0]))); // 3 straight lines
                 l.push(line(rotate([1-h1/2,h0/2]), rotate([-1+h1/2,-h0/2]), rotate(scl([Math.cos(Math.PI/3), -Math.sin(Math.PI/3)], lineWidth))));
                 l.push(line(rotate([1-h1/2,-h0/2]), rotate([-1+h1/2,h0/2]), rotate(scl([Math.cos(-Math.PI/3), -Math.sin(-Math.PI/3)], lineWidth))));
                 break;
        case 1:  l.push(line(rotate([0,h0]), rotate([0,-h0]), rotate([lineWidth, 0]))); // straight line + 2 arcs #1
                 l.push(circle(c[0], h1, Math.PI-Math.PI/3 + rotation, Math.PI+Math.PI/3 + rotation));
                 l.push(circle(c[3], h1, -Math.PI/3 + rotation, +Math.PI/3 + rotation));
                 break;
        case 2:  l.push(line(rotate([0,h0]), rotate([0,-h0]), rotate([lineWidth, 0]))); // straight line + 2 arcs #2
                 l.push(circle(rotate([0,2*h0]), 1+h1, -Math.PI/2-Math.PI/6 + rotation, -Math.PI/2+Math.PI/6 + rotation));
                 l.push(circle(rotate([0,-2*h0]), 1+h1, Math.PI/2-Math.PI/6 + rotation, Math.PI/2+Math.PI/6 + rotation));
                 break;
        case 3:  l.push(circle(c[0], h1, Math.PI-Math.PI/3 + rotation, Math.PI+Math.PI/3 + rotation)); // 3 arcs #1
                 l.push(circle(c[2], h1, -2*Math.PI/3 + rotation, 0 + rotation));
                 l.push(circle(c[4], h1, 0 + rotation, 2*Math.PI/3 + rotation));
                 break;
        default: l.push(circle(rotate([0,2*h0]), 1+h1, -Math.PI/2-Math.PI/6 + rotation, -Math.PI/2+Math.PI/6 + rotation)); // 3 arcs #2
                 l.push(circle(rotate([-1-h1, h0]), 1+h1, 0 + rotation, -Math.PI/3 + rotation));
                 l.push(circle(c[5], h1, Math.PI/3 + rotation, Math.PI + rotation));
                 break;
    }

    // shuffle lines and draw
    l.sort((a,b) => Math.random()-.5);
    l.map(p => poly.draw(t, p));

    // background
    const p0 = poly.create();
    p0.addPoints(...c.map(p => ts(p)));

    if (lineWidth < 0.35) p0.addHatching(Math.PI/4, 1);
    poly.draw(t, p0);
}