diff --git a/beautiful-racket/br/demo/hdl/DMux.hdl.rkt b/beautiful-racket/br/demo/hdl/DMux.hdl.rkt
index 189558b..fc3bc99 100644
--- a/beautiful-racket/br/demo/hdl/DMux.hdl.rkt
+++ b/beautiful-racket/br/demo/hdl/DMux.hdl.rkt
@@ -16,6 +16,7 @@ CHIP DMux {
     OUT a, b;
 
     PARTS:
-    And(a=in, b=sel, out=a);
+    Not(in=sel, out=not-sel);
+    And(a=in, b=not-sel, out=a);
     And(a=in, b=sel, out=b);
 }
diff --git a/beautiful-racket/br/demo/hdl/DMux4Way-test.rkt b/beautiful-racket/br/demo/hdl/DMux4Way-test.rkt
new file mode 100644
index 0000000..404fc95
--- /dev/null
+++ b/beautiful-racket/br/demo/hdl/DMux4Way-test.rkt
@@ -0,0 +1,28 @@
+#lang racket
+(require "DMux4Way.hdl.rkt")
+(require rackunit)
+
+(DMux4Way-in (random 2))
+(DMux4Way-sel #b00)
+(check-equal? (DMux4Way-a) (DMux4Way-in))
+(check-equal? (DMux4Way-b) 0)
+(check-equal? (DMux4Way-c) 0)
+(check-equal? (DMux4Way-d) 0)
+
+(DMux4Way-sel #b01)
+(check-equal? (DMux4Way-a) 0)
+(check-equal? (DMux4Way-b) (DMux4Way-in))
+(check-equal? (DMux4Way-c) 0)
+(check-equal? (DMux4Way-d) 0)
+
+(DMux4Way-sel #b10)
+(check-equal? (DMux4Way-a) 0)
+(check-equal? (DMux4Way-b) 0)
+(check-equal? (DMux4Way-c) (DMux4Way-in))
+(check-equal? (DMux4Way-d) 0)
+
+(DMux4Way-sel #b11)
+(check-equal? (DMux4Way-a) 0)
+(check-equal? (DMux4Way-b) 0)
+(check-equal? (DMux4Way-c) 0)
+(check-equal? (DMux4Way-d) (DMux4Way-in))
diff --git a/beautiful-racket/br/demo/hdl/Dmux-test.rkt b/beautiful-racket/br/demo/hdl/Dmux-test.rkt
new file mode 100644
index 0000000..f1dc0dc
--- /dev/null
+++ b/beautiful-racket/br/demo/hdl/Dmux-test.rkt
@@ -0,0 +1,23 @@
+#lang racket
+(require "DMux.hdl.rkt")
+(require rackunit)
+
+(DMux-in 0)
+(DMux-sel 0)
+(check-equal? (DMux-a) 0)
+(check-equal? (DMux-b) 0)
+
+(DMux-in 0)
+(DMux-sel 1)
+(check-equal? (DMux-a) 0)
+(check-equal? (DMux-b) 0)
+
+(DMux-in 1)
+(DMux-sel 0)
+(check-equal? (DMux-a) 1)
+(check-equal? (DMux-b) 0)
+
+(DMux-in 1)
+(DMux-sel 1)
+(check-equal? (DMux-a) 0)
+(check-equal? (DMux-b) 1)
diff --git a/beautiful-racket/br/demo/hdl/Dmux4Way.hdl.rkt b/beautiful-racket/br/demo/hdl/Dmux4Way.hdl.rkt
index dd941c8..3d5ccfd 100644
--- a/beautiful-racket/br/demo/hdl/Dmux4Way.hdl.rkt
+++ b/beautiful-racket/br/demo/hdl/Dmux4Way.hdl.rkt
@@ -14,9 +14,11 @@
  */
 
 CHIP DMux4Way {
+    // todo: how should sel subscripting work?
     IN in, sel[2];
-    OUT out;
+    OUT a, b, c, d;
 
     PARTS:
-    Not(in=sel[0], out=out);
+    DMux(in=in, sel[0]=sel, a=a, b=b);
+    DMux(in=in, sel[1]=sel, a=c, b=d); 
 }
\ No newline at end of file
diff --git a/beautiful-racket/br/demo/hdl/expander.rkt b/beautiful-racket/br/demo/hdl/expander.rkt
index e2404af..850fd0b 100644
--- a/beautiful-racket/br/demo/hdl/expander.rkt
+++ b/beautiful-racket/br/demo/hdl/expander.rkt
@@ -17,7 +17,7 @@
         (define-input-bus _input-pin _input-width ...) ...
         _part ...
         (provide prefixed-output-pin ...)
-        (define-output-bus prefixed-output-pin (λ () (_output-pin)) _output-width ...) ...)))
+        (define-output-bus prefixed-output-pin _output-pin _output-width ...) ...)))
 
 
 (define #'(part _prefix [_suffix . _args] ...)
diff --git a/beautiful-racket/br/demo/hdl/parser.rkt b/beautiful-racket/br/demo/hdl/parser.rkt
index f560ebf..5b22dd9 100644
--- a/beautiful-racket/br/demo/hdl/parser.rkt
+++ b/beautiful-racket/br/demo/hdl/parser.rkt
@@ -20,7 +20,7 @@ part : partname /"(" pin-val-pair [/"," pin-val-pair]* /")" /";"
 
 /pin-val-pair : ID  [/"[" bus-range /"]"] /"=" pin-val
 
-@bus-range : NUMBER [/"." /"." NUMBER]
+@bus-range : (NUMBER | BINARY-NUMBER) [/"." /"." (NUMBER | BINARY-NUMBER)]
 
 @pin-val : ID
          | BINARY-NUMBER