diff --git a/fitnesse/FitNesseRoot/RecentChanges.wiki b/fitnesse/FitNesseRoot/RecentChanges.wiki
index 56d131a..5b73d8f 100644
--- a/fitnesse/FitNesseRoot/RecentChanges.wiki
+++ b/fitnesse/FitNesseRoot/RecentChanges.wiki
@@ -1,4 +1,4 @@
-|TranscendentalLisp.Recursion||10:47:57 Fri, Nov 24, 2017|
+|TranscendentalLisp.Recursion||10:09:13 Sun, Nov 26, 2017|
 |TranscendentalLisp||16:15:14 Fri, Mar 17, 2017|
 |TranscendentalLisp.Macros||10:10:15 Mon, Mar 13, 2017|
 |TranscendentalLisp.MacroTests||10:07:00 Mon, Mar 13, 2017|
diff --git a/fitnesse/FitNesseRoot/TranscendentalLisp/Recursion.wiki b/fitnesse/FitNesseRoot/TranscendentalLisp/Recursion.wiki
index 363377e..52cc1e7 100644
--- a/fitnesse/FitNesseRoot/TranscendentalLisp/Recursion.wiki
+++ b/fitnesse/FitNesseRoot/TranscendentalLisp/Recursion.wiki
@@ -25,4 +25,5 @@ Test recursion capabilities of various functions.
 | check | evaluate text | (apply 'progn big-list)                                        | 1          |
 | check | evaluate text | (eval (append `(let ,(list-of '(x 20) 10000)) big-list))       | 1          |
 | check | evaluate text | (apply 'cond (list-of '((= 1 2) 1) 10000))                     | NIL        |
-| check | evaluate text | (eval (append '(case :a) (list-of '((:b :c :d) 1) 10000)))             | NIL        |
+| check | evaluate text | (eval (append '(case :a) (list-of '((:b :c :d) 1) 10000)))     | NIL        |
+| check | evaluate text | (nested-list 2000)                                             | =~/\)\)$/  |
diff --git a/lisp/util/list-builder.lisp b/lisp/util/list-builder.lisp
index b0501be..11b4151 100644
--- a/lisp/util/list-builder.lisp
+++ b/lisp/util/list-builder.lisp
@@ -24,3 +24,10 @@
 (defun list-of-tail (seed item size)
   (if (< size 1) seed
     (recur (cons item seed) item (- size 1))))
+
+(defun nested-list (size)
+  (nested-list-tail () size))
+
+(defun nested-list-tail (seed size)
+  (if (< size 1) seed
+    (recur (cons seed nil) (- size 1))))
diff --git a/src/sexpression/Cons.java b/src/sexpression/Cons.java
index 52fbf50..4789224 100644
--- a/src/sexpression/Cons.java
+++ b/src/sexpression/Cons.java
@@ -39,18 +39,19 @@ public class Cons extends SExpression {
 
     @Override
     public String toString() {
-        return toStringTailRecursive("(").invoke();
+        return toStringTailRecursive(new StringBuilder("(")).invoke();
     }
 
-    private TailCall<String> toStringTailRecursive(String precedingString) {
-        String leadingString = precedingString + first.toString();
+    private TailCall<String> toStringTailRecursive(StringBuilder leadingString) {
+        leadingString.append(first.toString());
 
         if (rest.isNull())
-            return done(leadingString + ")");
-        else if (rest.isCons())
-            return tailCall(() -> ((Cons) rest).toStringTailRecursive(leadingString + " "));
+            return done(leadingString.append(")").toString());
+        else if (rest.isCons()) {
+            return tailCall(() -> ((Cons) rest).toStringTailRecursive(leadingString.append(" ")));
+        }
 
-        return done(leadingString + " . " + rest.toString() + ")");
+        return done(leadingString.append(" . " + rest.toString() + ")").toString());
     }
 
 }