diff --git a/README.md b/README.md
index 643f8a6..b4aa821 100644
--- a/README.md
+++ b/README.md
@@ -2,3 +2,8 @@
 
 this is me (PRH) trying to learn some front end web dev because pixels are
 important despite my wishes.
+
+# notes
+
+## goal queue
+
diff --git a/src/wfc_wfchar.erl b/src/wfc_ltr.erl
similarity index 65%
rename from src/wfc_wfchar.erl
rename to src/wfc_ltr.erl
index 78b39e7..5ce8772 100644
--- a/src/wfc_wfchar.erl
+++ b/src/wfc_ltr.erl
@@ -1,10 +1,10 @@
-% @doc called wfchar to disambiguate from 
+% @doc called ltr to disambiguate from 
 %
 % mathematically, this is a variable like "a", "b", "c", etc
--module(wfc_wfchar).
+-module(wfc_ltr).
 
 -export_type([
-    wfchar/0
+    ltr/0
 ]).
 
 -export([
@@ -22,17 +22,17 @@
 % - numbers ok
 % - no non-ascii chars
 
--opaque wfchar() :: {c, binary()}.
+-opaque ltr() :: {c, binary()}.
 
 %%-----------------------
 %% constructors/destructors
 %%-----------------------
 
--spec validate(WfChar) -> Result
-    when WfChar :: wfchar(),
+-spec validate(Ltr) -> Result
+    when Ltr    :: ltr(),
          Result :: ok
                  | {error, Reason :: string()}.
-% @doc validate if a candidate wfchar is well-formed and the inner binary is
+% @doc validate if a candidate ltr is well-formed and the inner binary is
 % legal
 
 validate({c, Binary}) ->
@@ -43,25 +43,25 @@ validate({c, Binary}) ->
             Error
     end;
 validate(Term) ->
-    Error = wfc_utils:emsg("wfc_wfchar:validate failed; malformed wfchar: ~p", [Term]),
+    Error = wfc_utils:emsg("wfc_ltr:validate failed; malformed ltr: ~p", [Term]),
     {error, Error}.
 
 
 -spec from_binary(Binary) -> Result
     when Binary :: binary(),
-         Result :: {ok, wfchar()}
+         Result :: {ok, ltr()}
                  | {error, Reason :: string()}.
 % @doc
-% make sure the binary is a legal wfchar and wrap it in a {c, Binary} tuple
+% make sure the binary is a legal ltr and wrap it in a {c, Binary} tuple
 % @end
 
 %% initial char must be [a-z]
 from_binary(<<L:8, Rest/binary>>) when $a =< L, L =< $z ->
     new2(<<L>>, Rest);
 from_binary(Char = <<L:8, _/binary>>) ->
-    {error, wfc_utils:emsg("wfc_wfchar:from_binary(~p): illegal lead character: ~p", [Char, L])};
+    {error, wfc_utils:emsg("wfc_ltr:from_binary(~p): illegal lead character: ~p", [Char, L])};
 from_binary(Char) ->
-    wfc_utils:err("wfc_wfchar:from_binary(~p): malformed argument", [Char]).
+    wfc_utils:err("wfc_ltr:from_binary(~p): malformed argument", [Char]).
 
 %% rest must be [A-Za-z0-9_]
 new2(Acc, <<L:8, Rest/binary>>) when       ($A =< L andalso L =< $Z)
@@ -73,11 +73,11 @@ new2(Acc, <<>>) ->
     {ok, {c, Acc}};
 new2(Acc, Rest = <<BadChar:8, _/binary>>) ->
     WholeChar = <<Acc/binary, Rest/binary>>,
-    Error     = wfc_utils:emsg("wfc_wfchar:new2(~p, ~p): illegal character in wfchar: ~p; WholeChar: ~p", [Acc, Rest, BadChar, WholeChar]),
+    Error     = wfc_utils:emsg("wfc_ltr:new2(~p, ~p): illegal character in ltr: ~p; WholeChar: ~p", [Acc, Rest, BadChar, WholeChar]),
     {error, Error}.
 
 
 
--spec to_binary(wfchar()) -> binary().
+-spec to_binary(ltr()) -> binary().
 
 to_binary({c, X}) -> X.
diff --git a/src/wfc_word.erl b/src/wfc_word.erl
index 53bbb47..2a74ad0 100644
--- a/src/wfc_word.erl
+++ b/src/wfc_word.erl
@@ -1,4 +1,4 @@
-% @doc a word is an ordset of wfchars
+% @doc a word is an ordset of ltrs
 %
 % multiplication is implied in a word
 %
@@ -15,12 +15,12 @@
     %% constructors
     one/0,
     validate/1,
-    from_wfchars/1, to_wfchars/1,
+    from_ltrs/1, to_ltrs/1,
     %% ops
     mul/2, mul/1
 ]).
 
--opaque word() :: {w, ordsets:ordset(wfc_wfchar:wfchar())}.
+-opaque word() :: {w, ordsets:ordset(wfc_ltr:ltr())}.
 
 %%----------------------------
 %% constructor
@@ -32,26 +32,26 @@ one() ->
     {w, []}.
 
 
-validate(_)   -> error(nyi).
-to_wfchars(_) -> error(nyi).
+validate(_) -> error(nyi).
+to_ltrs(_)  -> error(nyi).
 
--spec from_wfchars(WfChars) -> Result
-    when WfChars :: list(wfc_char:wfchar()),
+-spec from_ltrs(Ltrs) -> Result
+    when Ltrs :: list(wfc_ltr:ltr()),
          Result  :: {ok, word()}
                   | {error, Reason :: string()}.
 
-from_wfchars(Chars) ->
-    from_wfchars(ordsets:from_list(Chars), []).
+from_ltrs(Chars) ->
+    from_ltrs(ordsets:from_list(Chars), []).
 
 
-%% validate each char
-from_wfchars([WfChar | Rest], Acc) ->
-    case wfc_wfchar:validate(WfChar) of
-        ok    -> from_wfchars(Rest, [WfChar | Acc]);
+%% validate each letter
+from_ltrs([Ltr | Rest], Acc) ->
+    case wfc_ltr:validate(Ltr) of
+        ok    -> from_ltrs(Rest, [Ltr | Acc]);
         Error -> Error
     end;
 % done, all good
-from_wfchars([], Acc) ->
+from_ltrs([], Acc) ->
     {ok, {w, lists:reverse(Acc)}}.
 
 
@@ -59,24 +59,17 @@ from_wfchars([], Acc) ->
 %% ops
 %%----------------------------
 
--spec mul(word(), word()) -> Result
-    when Result :: {ok, word()}
-                 | {error, Reason :: string()}.
+-spec mul(word(), word()) -> word().
 % @doc product of two words
+%
+% assumes the words are valid
 
 mul({w, X}, {w, Y}) ->
-    case from_wfchars(ordsets:union(X, Y)) of
-        Result = {ok, _} -> Result;
-        Error            -> Error
-    end.
+    {w, ordsets:union(X, Y)}.
 
 
--spec mul(Words) -> Result
-    when Words  :: [word()],
-         Result :: {ok, word()}
-                 | {error, Reason},
-         Reason :: string().
+-spec mul([word()]) -> word().
 % @doc multiply a list of words together
 
 mul([Word | Rest]) -> mul(Word, mul(Rest));
-mul([])            -> {ok, one()}.
+mul([])            -> one().