2f:T735,class RobinsonTriangle { constructor({ points, type, depth = 0 }) { this.type = type; this.points = points; this.depth = depth; } get path() { let [a, b, c] = this.points; return lineGen([b, a, c]); } get svg() { let [a, b, c] = this.points; let strokeWidth = 0.1 * Math.pow(0.87, depth); return htl.svg` `; } get color() { return this.type === "acute" ? "steelblue" : "rgb(160,40,5)"; } flip() { let [a, b, c] = this.points; return new RobinsonTriangle({ type: this.type, points: [a, c, b] }); } subdivide() { let [a, b, c] = this.points; if (this.type === "acute") { let p = lerpxy(a, b, 1 / PHI); return [ new RobinsonTriangle({ type: "acute", points: [c, p, b], depth: this.depth + 1 }), new RobinsonTriangle({ type: "obtuse", points: [p, c, a], depth: this.depth + 1 }) ]; } else { let q = lerpxy(b, a, 1 / PHI); let r = lerpxy(b, c, 1 / PHI); return [ new RobinsonTriangle({ type: "obtuse", points: [r, c, a], depth: this.depth + 1 }), new RobinsonTriangle({ type: "obtuse", points: [q, r, b], depth: this.depth + 1 }), new RobinsonTriangle({ type: "acute", points: [r, q, a], depth: this.depth + 1 }) ]; } } }30:[] 2d:{"title":"Penrose","cells":[{"id":0,"value":"# Penrose","pinned":false,"hidden":false,"mode":"md"},{"id":17,"value":"","pinned":false,"hidden":false,"mode":"html"},{"id":189,"value":"viewof depth = Inputs.range([0, 10], { label: \"Depth\", step: 1, value: 4 })","pinned":false,"hidden":false,"mode":"ojs"},{"id":394,"value":"shapes.find((s) => s.type === \"obtuse\")?.subdivide()","pinned":true,"hidden":false,"mode":"ojs"},{"id":163,"value":"shapes = {\n let size = 10;\n let rv = Array.from(\n { length: 10 },\n (d, i) =>\n new RobinsonTriangle({\n type: \"acute\",\n points: [\n { x: 0, y: 0 },\n {\n x: Math.cos((TAU / 10) * i) * size,\n y: Math.sin((TAU / 10) * i) * size\n },\n {\n x: Math.cos((TAU / 10) * (i + 1)) * size,\n y: Math.sin((TAU / 10) * (i + 1)) * size\n }\n ]\n })\n ).map((s, i) => (i % 2 ? s.flip() : s));\n for (let i = 0; i < depth; i++) {\n rv = rv.flatMap((s, j) => s.subdivide());\n }\n return rv;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":106,"value":"$2f","pinned":true,"hidden":false,"mode":"ojs"},{"id":63,"value":"lineGen = d3.line().x(d => d.x).y(d => d.y)","pinned":true,"hidden":false,"mode":"ojs"},{"id":7,"value":"deg = (d) => d / 360 * TAU","pinned":true,"hidden":true,"mode":"ojs"},{"id":9,"value":"TAU = Math.PI * 2","pinned":false,"hidden":false,"mode":"ojs"},{"id":212,"value":"lerp = (a, b, t) => a + (b - a) * t","pinned":false,"hidden":true,"mode":"ojs"},{"id":324,"value":"lerpxy = (p1, p2, t) => ({ x: lerp(p1.x, p2.x, t), y: lerp(p1.y, p2.y, t) })","pinned":true,"hidden":false,"mode":"ojs"},{"id":316,"value":"PHI = (1 + Math.sqrt(5)) / 2","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W30","stdlib":"1","titling":"auto"}