diff --git a/rhs/rhs.rkt b/rhs/rhs.rkt
index 66a0739..a78bc30 100644
--- a/rhs/rhs.rkt
+++ b/rhs/rhs.rkt
@@ -773,3 +773,11 @@ Licensed under GPL (2 or 3? FIXME)
 	(let ((lr (partition* (compose not pair?) t)))
 	  (cons (fst lr) (levels (concat (snd lr))))))))
 
+
+
+(module+ test
+  (require rackunit)
+  (check-equal? (drop 2 '(1 2 3 4 5 6)) '(3 4 5 6))
+  (check-equal? (transpose '((1 2) (3 4))) '((1 3) (2 4)))
+  )
+
diff --git a/rsc3/examples/ring3.rkt b/rsc3/examples/ring3.rkt
new file mode 100644
index 0000000..31ae1eb
--- /dev/null
+++ b/rsc3/examples/ring3.rkt
@@ -0,0 +1,30 @@
+#lang racket
+
+(require rsc3)
+
+
+;; from rsc3/help/ugen/binary-ops/ring3.help.scm
+
+
+;; make group 1
+(with-sc3 (lambda (fd) (send fd (g-new1 1 add-to-tail 0))))
+
+(audition
+ (out 0 (mul (ring4 (f-sin-osc ar 800 0)
+                    (f-sin-osc ar (x-line kr 200 500 5 do-nothing) 0))
+             0.125)))
+
+(let ((a (f-sin-osc ar 800 0))
+      (b (f-sin-osc ar (x-line kr 200 500 5 do-nothing) 0)))
+  (audition
+   (out 0 (mul (sub (mul3 a a b) (mul3 a b b)) 
+               0.125))))
+
+
+(audition
+ (out 0 (mul (ring3 (f-sin-osc ar 800 0)
+                    (f-sin-osc ar (x-line kr 200 500 5 do-nothing) 0))
+             0.125)))
+
+;; to stop sound and reset nodes/groups
+;; (with-sc3 reset)