Add the missing general-base pattern drawing code

code/patterns/patterns_genbase.rb

@@ -0,0 +1,62 @@
+require 'victor'
+
+BASE = 4
+DIRS = 7
+
+def sum_digits(n)
+  x = n % BASE
+  x == 0 ? BASE : x
+end
+
+def step(x, y, n, dir)
+  return [n*Math.cos(2*Math::PI/DIRS*dir), n*Math.sin(2*Math::PI/DIRS*dir), (dir+1) % DIRS]
+end
+
+def run_number(number)
+  counter = 1
+  x, y, dir = 0.0, 0.0, 0
+  line_stack = [[0,0]]
+
+  (BASE/BASE.gcd(number) * DIRS).times do |i|
+    dx, dy, dir = step(x,y, sum_digits(i*number), dir)
+    x += dx
+    y += dy
+    line_stack << [x,y]
+  end
+
+  puts line_stack.to_s
+  return make_svg(line_stack)
+end
+
+def make_svg(line_stack)
+  line_length = 20
+  xs = line_stack.map { |c| c[0] }
+  ys = line_stack.map { |c| c[1] }
+  
+  x_offset = -xs.min
+  y_offset = -ys.min
+  svg_coords = ->(p) {
+    nx, ny = p
+    [(nx+x_offset)*line_length + line_length/2, (ny+y_offset)*line_length + line_length/2]
+  }
+  
+  max_width = (xs.max - xs.min).abs * line_length + line_length
+  max_height = (ys.max - ys.min).abs * line_length + line_length
+  svg = Victor::SVG.new width: max_width, height: max_height
+  
+  style = { stroke: 'black', stroke_width: 5 }
+  svg.build do
+    line_stack.each_cons(2) do |pair|
+      p1, p2 = pair
+      x1, y1 = svg_coords.call(p1)
+      x2, y2 = svg_coords.call(p2)
+      line x1: x1, y1: y1, x2: x2, y2: y2, style: style
+      circle cx: x2, cy: y2, r: line_length/6, style: style, fill: 'black'
+    end
+  end
+  return svg
+end
+
+(1..10).each do |i|
+  run_number(i).save "pattern_#{i}"
+end