diff --git a/chord.lua b/chord.lua
index 34e5518..51d62da 100644
--- a/chord.lua
+++ b/chord.lua
@@ -336,6 +336,20 @@ function ChordBuilder:clone()
   return b
 end
 
+-- extensions is a table of 4 elements, each element being either 0 or 1 or false or true
+-- the first element is the seventh,
+-- the second is the ninth,
+-- the third is the eleventh,
+-- the fourth is the thirteenth
+function ChordBuilder:extend(extensions)
+  local b = self:clone()
+  b.seventh = (extensions[1]==1 or extensions[1]==true)
+  b.ninth = (extensions[2]==1 or extensions[2]==true)
+  b.eleventh = (extensions[3]==1 or extensions[3]==true)
+  b.thirteenth = (extensions[4]==1 or extensions[4]==true)
+  return b
+end
+
 function ChordBuilder:withSeventh()
   local b = self:clone()
   b.seventh = true
diff --git a/run_utests.lua b/run_utests.lua
index 216cd66..3de019d 100644
--- a/run_utests.lua
+++ b/run_utests.lua
@@ -13,4 +13,4 @@ require('test/tracks/test_clip_array')
 require('test/tracks/test_event')
 require('test/tracks/test_event_array')
 
-os.exit( lu.LuaUnit.run() )
\ No newline at end of file
+os.exit( lu.LuaUnit.run() )
diff --git a/scale.lua b/scale.lua
index adc55b1..640d23d 100644
--- a/scale.lua
+++ b/scale.lua
@@ -106,6 +106,22 @@ function Scale:to_the_right_on_circle_of_5ths(iterations)
     :to_the_right_on_circle_of_5ths(iterations -1)
 end
 
+--[[
+  Warning: only works for ionian scales
+]]
+function Scale:circle_of_5ths_rotate(iterations)
+  if(iterations == 0) then
+    return self
+  elseif(iterations < 0) then
+    return self:to_the_left_on_circle_of_5ths(-iterations)
+  elseif(iterations > 0) then
+    return self:to_the_right_on_circle_of_5ths(iterations)
+  else
+    return "Error"
+  end
+end
+
+
 --[[
   Returns a new scale based on self, rotated from note_offset
   note_offset: 
diff --git a/test/test_scale.lua b/test/test_scale.lua
index 3a2e9c6..9f2ee41 100644
--- a/test/test_scale.lua
+++ b/test/test_scale.lua
@@ -359,4 +359,26 @@ function TestScale:testGetDistance()
   luaunit.assertEquals(f_sharp_maj:get_distance(g_flat_min), 2)
   luaunit.assertEquals(f_sharp_maj:get_distance(d_sharp_min), 0)
   luaunit.assertEquals(f_sharp_maj:get_distance(d_sharp_min_harm), 1)
-end
\ No newline at end of file
+end
+
+function TestScale:test_c5ths_totheleft()
+  local c_major = Scale.c_major()
+  local next = c_major:to_the_left_on_circle_of_5ths(1)
+  -- print(next:tostring())
+  for i=1,11 do
+      next = next:to_the_left_on_circle_of_5ths(1)
+      -- print(next:tostring())
+  end
+  luaunit.assertEquals(next, Scale.c_major())
+end
+
+function TestScale:test_c5ths_totheright()
+  local c_major = Scale.c_major()
+  local next = c_major:to_the_right_on_circle_of_5ths(1)
+  -- print(next:tostring())
+  for i=1,11 do
+      next = next:to_the_right_on_circle_of_5ths(1)
+      -- print(next:tostring())
+  end
+  luaunit.assertEquals(next, Scale.c_major())
+end