diff --git a/README.md b/README.md
index 51076ec..7cb75d1 100644
--- a/README.md
+++ b/README.md
@@ -107,7 +107,7 @@ Turn the turtle clockwise by this `angle`, expressed in degrees with respect to
 
 Turn the turtle to face `angle`, expressed in degrees with respect to the X axis. If `angle` is not a number, throw an exception.
                 
-**TODO: Note that 180&deg; is currently straight up; this is not intended, it is intended that 0&deg; should be straight up, and this change will be made 
+**TODO**: Note that 180&deg; is currently straight up; this is not intended, it is intended that 0&deg; should be straight up, and this change will be made 
                 before version 1.0.
 
 ## Licence
diff --git a/index.html b/index.html
index 7797a01..4105eae 100644
--- a/index.html
+++ b/index.html
@@ -7,10 +7,10 @@
     <body>
         <h1>Tittle: Turtles in <a href="https://github.com/babashka/scittle/tree/main">Scittle</a></h1>
         <svg id="playing-field"
-            stype="width: 700; height: 700"
+            stype="width: 700; height: 900"
             version="1.1"
             width="700"
-            height="700"
+            height="900"
             xmlns="http://www.w3.org/2000/svg"
             xmlns:svg="http://www.w3.org/2000/svg">
 
@@ -73,7 +73,7 @@
                 "Turn the turtle to face `angle`, expressed in degrees with respect to the
                 X axis. If `angle` is not a number, throw an exception.
                 
-                **TODO: Note that 180&deg; is currently straight up; this is not intended, it 
+                **TODO**: Note that 180&deg; is currently straight up; this is not intended, it 
                 is intended that 0&deg; should be straight up, and this change will be made 
                 before version 1.0."
                 [angle]
@@ -127,6 +127,7 @@
                             (.setAttribute elt "x2" x)
                             (.setAttribute elt "y2" y)
                             (.setAttribute elt "stroke" (or (:ink @turtle) "blue"))
+                            (.setAttribute elt "stroke-width" (or (:nib @turtle) 3))
                             (.appendChild playing-field elt)))
                     (swap! turtle assoc :x x :y y))))
 
@@ -173,6 +174,13 @@
                 (when (string? colour)
                     (swap! turtle assoc :ink colour)))
 
+ 
+            (defn set-nib!
+                "Set the nib (width) of the pen to this `n`, which should be a number."
+                [n]
+                (when (number-or-error! n)
+                    (swap! turtle assoc :nib n)))       
+
             (defn draw-tree!
                 "Draw a tree. This is a fairly crude tree-drawing algorithm; 
                  there's lots of ways it can be improved, consider it a place
@@ -194,6 +202,7 @@
                 (log-turtle!)
                 (when (> depth 0)
                     (pen-down!)
+                    (set-nib! (if (<= depth 2) 4 (- depth 2)))
                     (set-ink! (if (<= depth 2) "green" "brown"))
                     (move! length)
                     (turn! curvature)
@@ -241,16 +250,17 @@
             (log-turtle!)
             (pen-up!)
             (log-turtle!)
-            (move-to! 350 700)
+            (move-to! 350 500)
             (log-turtle!)
-            (turn-to! 180)
-            (draw-tree! 100 20 16 8 0.2 0.8 8)
-            (set-ink! "blue")
             (doall (map #(let [v (* 16 (mod % 16))
-                                c (str "rgb(" v "," v "," (- 256 v)")")]
+                                c (str "rgb(" v "," 128 "," (- 256 v)")")]
                                 (set-ink! c)
                                 (draw-polygon! % 100)) 
-                        (range 3 16)))
+                        (range 3 24)))
+            (turn-to! 180)
+            (set-ink! "blue")
+            (set-nib! 2)
+            (draw-tree! 100 20 16 8 0.2 0.8 9)
         </script>
     </body>
 </html>
\ No newline at end of file
diff --git a/resources/cljs/tittle.cljs b/resources/cljs/tittle.cljs
index d6caee2..291fe9e 100644
--- a/resources/cljs/tittle.cljs
+++ b/resources/cljs/tittle.cljs
@@ -1,6 +1,6 @@
 (ns tittle)
 
-            (def turtle (atom {:theta 0 :x 0 :y 0 :pen :up :ink "blue"}))
+(def turtle (atom {:theta 0 :x 0 :y 0 :pen :up :nib 3 :ink "blue"}))
 
 (defn log-turtle!
   "Prints the state of the turtle to the browser console."
@@ -105,6 +105,7 @@
           (.setAttribute elt "x2" x)
           (.setAttribute elt "y2" y)
           (.setAttribute elt "stroke" (or (:ink @turtle) "blue"))
+          (.setAttribute elt "stroke-width" (or (:nib @turtle) 3))
           (.appendChild playing-field elt)))
       (swap! turtle assoc :x x :y y))))
 
@@ -151,6 +152,12 @@
   (when (string? colour)
     (swap! turtle assoc :ink colour)))
 
+(defn set-nib!
+  "Set the nib (width) of the pen to this `n`, which should be a number."
+  [n]
+  (when (number-or-error! n)
+    (swap! turtle assoc :nib n)))
+
 (defn draw-tree!
   "Draw a tree. This is a fairly crude tree-drawing algorithm; 
                  there's lots of ways it can be improved, consider it a place
