diff --git a/maze-get-set-root.scm b/maze-get-set-root.scm
new file mode 100644
index 00000000..988f1afe
--- /dev/null
+++ b/maze-get-set-root.scm
@@ -0,0 +1,20 @@
+;;; MAZE -- Constructs a maze on a hexagonal grid, written by Olin Shivers.
+
+(import (scheme base) (scheme read) (scheme write) (scheme time))
+
+(define (get-set-root s)
+  (let lp ((r s));; Find the last pair
+    (let ((next (cdr r)));; in the list. That's
+      (cond ((pair? next) (lp next));; the root r.
+
+            (else
+             (if (not (eq? r s));; Now zip down the list again,
+                 (let lp ((x s));; changing everyone's cdr to r.
+                   (let ((next (cdr x)))
+                     (cond ((not (eq? r next))
+                            (set-cdr! x r)
+                            (lp next))))))
+             r)))));; Then return r.
+
+(write
+  (get-set-root '()))