diff --git a/docs/api.md b/docs/api.md
index 56af35e..1393752 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -241,6 +241,36 @@ Parameters
 Drone.cylinder0() method
 ========================
 A version of cylinder that hollows out the middle.
+Drone.arc() method
+==================
+The arc() method can be used to create 1 or more 90 degree arcs in the horizontal or vertical planes.
+This method is called by cylinder() and cylinder0() and the sphere() and sphere0() methods.
+
+Parameters
+----------
+arc() takes a single parameter - an object with the following named properties...
+
+ * radius - The radius of the arc.
+ * blockType - The type of block to use - this is the block Id only (no meta). See [Data Values][dv].
+ * meta - The metadata value. See [Data Values][dv].
+ * orientation (default: 'horizontal') - the orientation of the arc - can be 'vertical' or 'horizontal'.
+ * stack (default: 1) - the height or length of the arc (depending on
+   the orientation - if orientation is horizontal then this parameter
+   refers to the height, if vertical then it refers to the length).
+ * strokeWidth (default: 1) - the width of the stroke (how many
+   blocks) - if drawing nested arcs it's usually a good idea to set
+   strokeWidth to at least 2 so that there are no gaps between each
+   arc. The arc method uses a [bresenham algorithm][bres] to plot
+   points along the circumference.
+ * fill - If true (or present) then the arc will be filled in.
+ * quadrants (default:
+   `{topleft:true,topright:true,bottomleft:true,bottomright:true}` - An
+   object with 4 properties indicating which of the 4 quadrants of a
+   circle to draw. If the quadrants property is absent then all 4
+   quadrants are drawn.
+
+[bres]: http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+[dv]: http://www.minecraftwiki.net/wiki/Data_values
 Drone.door() method
 ===================
 create a door - if a parameter is supplied an Iron door is created otherwise a wooden door is created.
@@ -257,8 +287,8 @@ Parameters
 ----------
  * doorType (optional - default wood) - If a parameter is provided then the door is Iron.
 
-Drone.sign method
-=================
+Drone.sign() method
+===================
 Signs must use block 63 (stand-alone signs) or 68 (signs on walls)
 
 Parameters
@@ -389,3 +419,61 @@ Drone Properties
  * z - The Drone's position along the north-south axis (z increases as you move south)
  * dir - The Drone's direction 0 is east, 1 is south , 2 is west and 3 is north.
 
+Extending Drone
+===============
+The Drone object can be easily extended - new buidling recipes/blue-prints can be added and can
+become part of a Drone's chain using the *static* method `Drone.extend`. 
+
+Drone.extend() static method
+============================
+Use this method to add new methods (which also become chainable global functions) to the Drone object.
+
+Parameters
+----------
+ * name - The name of the new method e.g. 'pyramid'
+ * function - The method body.
+
+Example
+-------
+
+    // submitted by [edonaldson][edonaldson]
+    Drone.extend('pyramid', function(block,height){
+        this.chkpt('pyramid');
+        for (var i = height; i > 0; i -= 2) {
+            this.box(block, i, 1, i).up().right().fwd();
+        }
+        return this.move('pyramid');      
+    });
+
+Once the method is defined (it can be defined in a new pyramid.js file) it can be used like so...
+
+    var d = new Drone();
+    d.pyramid(blocks.brick.stone, 12);
+
+... or simply ...
+
+    pyramid(blocks.brick.stone, 12);
+
+[edonaldson]: https://github.com/edonaldson
+
+Drone.blocktype() method
+========================
+Creates the text out of blocks. Useful for large-scale in-game signs.
+
+Parameters
+----------
+ 
+ * message - The message to create - (use `\n` for newlines)
+ * foregroundBlock (default: black wool) - The block to use for the foreground
+ * backgroundBlock (default: none) - The block to use for the background
+
+Example
+-------
+To create a 2-line high message using glowstone...
+
+    blocktype("Hello\nWorld",blocks.glowstone);
+
+![blocktype example][imgbt1]
+
+[imgbt1]: img/blocktype1.png
+
diff --git a/docs/img/blocktype1.png b/docs/img/blocktype1.png
new file mode 100644
index 0000000..f1c89ae
Binary files /dev/null and b/docs/img/blocktype1.png differ
diff --git a/src/main/javascript/drone/blocktype.js b/src/main/javascript/drone/blocktype.js
index f931c4d..e0abd21 100644
--- a/src/main/javascript/drone/blocktype.js
+++ b/src/main/javascript/drone/blocktype.js
@@ -296,8 +296,31 @@ load(__folder + "drone.js");
             }
         }
     }
-    //
-    // Creates the text out of blocks
+/************************************************************************
+Drone.blocktype() method
+========================
+Creates the text out of blocks. Useful for large-scale in-game signs.
+
+Parameters
+----------
+ 
+ * message - The message to create - (use `\n` for newlines)
+ * foregroundBlock (default: black wool) - The block to use for the foreground
+ * backgroundBlock (default: none) - The block to use for the background
+
+Example
+-------
+To create a 2-line high message using glowstone...
+
+    blocktype("Hello\nWorld",blocks.glowstone);
+
+![blocktype example][imgbt1]
+
+[imgbt1]: img/blocktype1.png
+
+***/
+
+
     //
     // message
     //   string with text to be displayed
@@ -310,6 +333,9 @@ load(__folder + "drone.js");
 
         this.chkpt('blocktext');
 
+        if (typeof fg == "undefined")
+            fg = blocks.black;
+
         var bmfg = this._getBlockIdAndMeta(fg);
         var bmbg = null;
         if (typeof bg != "undefined")
diff --git a/src/main/javascript/drone/drone.js b/src/main/javascript/drone/drone.js
index 977d8c6..1df85b6 100644
--- a/src/main/javascript/drone/drone.js
+++ b/src/main/javascript/drone/drone.js
@@ -277,6 +277,40 @@ A version of cylinder that hollows out the middle.
 ***/
 Drone.prototype.cylinder = function(block,radius,height){};
 Drone.prototype.cylinder0 = function(block,radius,height){};
+/************************************************************************
+Drone.arc() method
+==================
+The arc() method can be used to create 1 or more 90 degree arcs in the horizontal or vertical planes.
+This method is called by cylinder() and cylinder0() and the sphere() and sphere0() methods.
+
+Parameters
+----------
+arc() takes a single parameter - an object with the following named properties...
+
+ * radius - The radius of the arc.
+ * blockType - The type of block to use - this is the block Id only (no meta). See [Data Values][dv].
+ * meta - The metadata value. See [Data Values][dv].
+ * orientation (default: 'horizontal') - the orientation of the arc - can be 'vertical' or 'horizontal'.
+ * stack (default: 1) - the height or length of the arc (depending on
+   the orientation - if orientation is horizontal then this parameter
+   refers to the height, if vertical then it refers to the length).
+ * strokeWidth (default: 1) - the width of the stroke (how many
+   blocks) - if drawing nested arcs it's usually a good idea to set
+   strokeWidth to at least 2 so that there are no gaps between each
+   arc. The arc method uses a [bresenham algorithm][bres] to plot
+   points along the circumference.
+ * fill - If true (or present) then the arc will be filled in.
+ * quadrants (default:
+   `{topleft:true,topright:true,bottomleft:true,bottomright:true}` - An
+   object with 4 properties indicating which of the 4 quadrants of a
+   circle to draw. If the quadrants property is absent then all 4
+   quadrants are drawn.
+
+[bres]: http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+[dv]: http://www.minecraftwiki.net/wiki/Data_values
+***/
+Drone.prototype.arc = function(params) {};
+
 /************************************************************************
 Drone.door() method
 ===================
@@ -298,8 +332,8 @@ Parameters
 Drone.prototype.door = function(b){};
 Drone.prototype.door2 = function(b){};
 /************************************************************************
-Drone.sign method
-=================
+Drone.sign() method
+===================
 Signs must use block 63 (stand-alone signs) or 68 (signs on walls)
 
 Parameters
@@ -449,6 +483,43 @@ Drone Properties
  * z - The Drone's position along the north-south axis (z increases as you move south)
  * dir - The Drone's direction 0 is east, 1 is south , 2 is west and 3 is north.
 
+Extending Drone
+===============
+The Drone object can be easily extended - new buidling recipes/blue-prints can be added and can
+become part of a Drone's chain using the *static* method `Drone.extend`. 
+
+Drone.extend() static method
+============================
+Use this method to add new methods (which also become chainable global functions) to the Drone object.
+
+Parameters
+----------
+ * name - The name of the new method e.g. 'pyramid'
+ * function - The method body.
+
+Example
+-------
+
+    // submitted by [edonaldson][edonaldson]
+    Drone.extend('pyramid', function(block,height){
+        this.chkpt('pyramid');
+        for (var i = height; i > 0; i -= 2) {
+            this.box(block, i, 1, i).up().right().fwd();
+        }
+        return this.move('pyramid');      
+    });
+
+Once the method is defined (it can be defined in a new pyramid.js file) it can be used like so...
+
+    var d = new Drone();
+    d.pyramid(blocks.brick.stone, 12);
+
+... or simply ...
+
+    pyramid(blocks.brick.stone, 12);
+
+[edonaldson]: https://github.com/edonaldson
+
 ***/
 
 //
@@ -1365,11 +1436,12 @@ Drone Properties
     //
     var ops = ['up','down','left','right','fwd','back','turn',
                'chkpt','move',
-               'box','box0','boxa','prism','prism0','cylinder','cylinder0',
+               'box','box0','boxa','prism','prism0','cylinder','cylinder0','arc',
                'door','door2','sign','oak','spruce','birch','jungle',
                'rand','garden',
                'copy','paste'
               ];
+
     for (var i = 0;i < ops.length; i++){
         global[ops[i]] = function(op){
             return function(){