03: Fibonacci forever

03/fibomod.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+
+import math
+
+def fibomod(n):
+    values = [0, 1]
+    while not ( values[-2] == 1 and values[-1] == 0):
+        x = (values[-1] + values[-2]) % n
+        values.append(x)
+    return values[:-1]
+
+def fibopoint(cx, cy, r, p, n):
+    theta = 2 * math.pi * p / n
+    return ( cx + r * math.sin(theta), cy - r * math.cos(theta) )
+
+def fibopoly(cx, cy, r, n):
+    return [ fibopoint(cx, cy, r, p, n) for p in fibomod(n) ]
+
+def svgpoly(points):
+    ps = " ".join([ f"{x},{y}" for (x, y) in points ])
+    return f'<polygon points="{ps}" stroke="black" opacity="50%" fill="none" />'
+
+def svgline(p1, p2):
+    return f'<line x1="{p1[0]}" y1="{p1[1]}" x2="{p2[0]}" y2="{p2[1]}" stroke="black" opacity="20%"/>\n'
+
+def svglines(points):
+    lines = ""
+    for i in range(1, len(points)):
+        p2 = points[i]
+        p1 = points[i - 1]
+        lines += svgline(p1, p2)
+    lines += svgline(points[-1], points[0])
+    return lines
+
+print('<svg width="800" height="1200" xmlns="http://www.w3.org/2000/svg">')
+
+n = 2
+for j in range(11):
+    for i in range(7):
+        cx = 50 + i * 100
+        cy = 50 + j * 100
+        r = 40
+        print(svglines(fibopoly(cx, cy, r, n)))
+        n += 1
+
+print('</svg>')
+