Data update

Task/Pythagoras-tree/Dart/pythagoras-tree-1.dart

@@ -0,0 +1,23 @@
+import 'dart:math';
+import 'dart:io';
+
+void main() {
+  var basis = [(Point(-200.0, 0.0), Point(200.0, 0.0))];
+  final groups = Iterable.generate(12, (lvl) {
+    final basis0 = basis;
+    basis = [];
+    final lvlPolygons = basis0.map((pp) {
+      final (a, b) = pp;
+      final v =  Point((b - a).y, (a - b).x);
+      final (c, d) = (a + v, b + v);
+      final e = (c + d + v) * 0.5;
+      basis.addAll([(c, e), (e, d)]);
+      return '<polygon points="${[a, c, e, d, c, d, b].expand((p) => [p.x, p.y]).join(' ')}"/>';
+    }).join('\n');
+    rg(int step) => ((80 + (lvl - 2) * step) & 255).toRadixString(16).padLeft(2, '0');
+    return '<g fill="#${rg(20)}${rg(30)}18">\n$lvlPolygons\n</g>';
+  }).join('\n');
+  final (x, y) = basis.fold((0.0, 0.0), (p, pp) => (min(p.$1, pp.$1.x), min(p.$2, pp.$1.y)));
+  final attrs = 'viewBox="$x $y ${-x - x} ${-y}" stroke="white" xmlns="http://www.w3.org/2000/svg"';
+  File('Pythagor_tree.svg').writeAsString('<svg $attrs>\n$groups\n</svg>');
+}

Task/Pythagoras-tree/Dart/pythagoras-tree-2.dart

@@ -0,0 +1,45 @@
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MainApp());
+
+class MainApp extends StatelessWidget {
+  const MainApp({super.key});
+
+  @override
+  Widget build(BuildContext context) => FittedBox(
+      child: CustomPaint(painter: TreePainter(), size: const Size(2400, 1600)));
+}
+
+class TreePainter extends CustomPainter {
+  @override
+  void paint(Canvas canvas, Size size) {
+    final stroke = Paint()
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 0.9
+      ..color = Colors.white;
+    final fill = Paint()..style = PaintingStyle.fill;
+    canvas.drawColor(Colors.white, BlendMode.src);
+
+    const halfBase = Offset(200, 0);
+    var basis = [(size.bottomCenter(-halfBase), size.bottomCenter(halfBase))];
+    for (var lvl = 0; lvl < 12; lvl++) {
+      final path = Path();
+      final basis0 = basis;
+      basis = [];
+      for (var (a, b) in basis0) {
+        final v = Offset((b - a).dy, (a - b).dx);
+        final (c, d) = (a + v, b + v);
+        final e = (c + d + v) / 2;
+        basis.addAll([(c, e), (e, d)]);
+        path.addPolygon([a, c, e, d, c, d, b], true);
+      }
+      rg(int step) => (80 + (lvl - 2) * step) & 255;
+      canvas
+        ..drawPath(path, fill..color = Color.fromARGB(255, rg(20), rg(30), 18))
+        ..drawPath(path, stroke);
+    }
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => true;
+}