diff --git a/pkg/arvo/sys/hoon.hoon b/pkg/arvo/sys/hoon.hoon
index b259b1ed0..b3a390d2a 100644
--- a/pkg/arvo/sys/hoon.hoon
+++ b/pkg/arvo/sys/hoon.hoon
@@ -1603,6 +1603,7 @@
     d(l a(r l.d))
   ::
   ++  rep                                               ::  reduce to product
+    ~/  %rep
     |*  b/_=>(~ |=({* *} +<+))
     |-
     ?~  a  +<+.b
@@ -1692,12 +1693,16 @@
     a(n n.a(q (b p.n.a q.n.a)), l $(a l.a), r $(a r.a))
   ::
   ++  wyt                                               ::  depth of map
-    |-  ^-  @
+    =<  $
+    ~%  %wyt  +  ~
+    |.  ^-  @
     ?~(a 0 +((add $(a l.a) $(a r.a))))
   ::
   ++  key                                               ::  set of keys
+    =<  $
+    ~/  %key
     =+  b=`(set _?>(?=(^ a) p.n.a))`~
-    |-  ^+  b
+    |.  ^+  b
     ?~  a   b
     $(a r.a, b $(a l.a, b (~(put in b) p.n.a)))
   ::
diff --git a/pkg/urbit/include/jets/w.h b/pkg/urbit/include/jets/w.h
index c63026a19..5b202c8fd 100644
--- a/pkg/urbit/include/jets/w.h
+++ b/pkg/urbit/include/jets/w.h
@@ -86,10 +86,12 @@
     u3_noun u3wdb_has(u3_noun);
     u3_noun u3wdb_int(u3_noun);
     u3_noun u3wdb_jab(u3_noun);
+    u3_noun u3wdb_key(u3_noun);
     u3_noun u3wdb_put(u3_noun);
 #   define u3wdb_tap u3wdi_tap
     u3_noun u3wdb_uni(u3_noun);
     u3_noun u3wdb_run(u3_noun);
+#   define u3wdb_wyt u3wdi_wyt
 
     u3_noun u3wdi_bif(u3_noun);
     u3_noun u3wdi_del(u3_noun);
diff --git a/pkg/urbit/jets/d/by_key.c b/pkg/urbit/jets/d/by_key.c
new file mode 100644
index 000000000..62a8d510d
--- /dev/null
+++ b/pkg/urbit/jets/d/by_key.c
@@ -0,0 +1,35 @@
+/* j/4/by_run.c
+**
+*/
+#include "all.h"
+
+/* internal functions
+ */
+static u3_noun
+_by_key(u3_noun a, u3_noun set)
+{
+  if (u3_nul == a) {
+    return u3k(set);
+  } else {
+    u3_noun n_a, l_a, r_a;
+    u3_noun p_n_a, q_n_a;
+    u3x_trel(a, &n_a, &l_a, &r_a);
+    u3x_cell(n_a, &p_n_a, &q_n_a);
+
+    u3_noun with_set = u3qdi_put(set, p_n_a);
+    u3_noun left_set = _by_key(l_a, with_set);
+    u3z(with_set);
+    u3_noun right_set = _by_key(r_a, left_set);
+    u3z(left_set);
+
+    return right_set;
+  }
+}
+
+u3_noun
+u3wdb_key(u3_noun cor)
+{
+  u3_noun a;
+  u3x_mean(cor, u3x_con_sam, &a, 0);
+  return _by_key(a, 0);
+}
diff --git a/pkg/urbit/jets/tree.c b/pkg/urbit/jets/tree.c
index 283fae819..4150cc1c2 100644
--- a/pkg/urbit/jets/tree.c
+++ b/pkg/urbit/jets/tree.c
@@ -1636,7 +1636,9 @@ static c3_c* _141_two__in_ha[] = {
     0
   };
 
-  static u3j_harm _141_two__by_run_a[] = {{".2", u3wdb_run, c3y}, {}};
+  static u3j_harm _141_two__by_key_a[] = {{".2", u3wdb_key}, {}};
+  static u3j_harm _141_two__by_run_a[] = {{".2", u3wdb_run}, {}};
+  static u3j_harm _141_two__by_wyt_a[] = {{".2", u3wdb_wyt}, {}};
 
   static u3j_harm _141_two__by_tap_a[] = {{".2", u3wdb_tap, c3y}, {}};
   static c3_c* _141_two__by_tap_ha[] = {
@@ -1657,9 +1659,11 @@ static u3j_core _141_two__by_d[] =
     { "has", 7, _141_two__by_has_a, 0, _141_two__by_has_ha },
     // { "int", 7, _141_two__by_int_a, 0, _141_two__by_int_ha },
     { "jab", 7, _141_two__by_jab_a, 0, _141_two__by_jab_ha },
+    { "key", 7, _141_two__by_key_a },
     { "put", 7, _141_two__by_put_a, 0, _141_two__by_put_ha },
     { "run", 7, _141_two__by_run_a },
     { "tap", 7, _141_two__by_tap_a, 0, _141_two__by_tap_ha },
+    { "wyt", 3, _141_two__by_wyt_a },
     // { "uni", 7, _141_two__by_uni_a, 0, _141_two__by_uni_ha },
     {}
   };