diff --git a/include/continuable/continuable.hpp b/include/continuable/continuable.hpp
index 76ca6c5..3138878 100644
--- a/include/continuable/continuable.hpp
+++ b/include/continuable/continuable.hpp
@@ -63,14 +63,14 @@ using continuable = typename detail::trait_of<
   Args...
 >::continuable;
 
-/// Defines a copyable callback type which uses the
-/// function2 backend for the continuable type erasure.
+/// Defines a non-copyable continuation type which uses the
+/// function2 backend for type erasure.
 ///
-/// Usable like: `callback<int, float>`
-// template <typename... Args>
-// using promise = typename detail::trait_of<
-//   Args...
-// >::promise;
+/// Usable like: `unique_continuable<int, float>`
+template <typename... Args>
+using unique_continuable = typename detail::unique_trait_of<
+  Args...
+>::continuable;
 
 /// Defines a non-copyable promise type which using the
 /// function2 backend for type erasure.
@@ -81,15 +81,6 @@ using promise = typename detail::unique_trait_of<
   Args...
 >::promise;
 
-/// Defines a non-copyable callback type which uses the
-/// function2 backend for the continuable type erasure.
-///
-/// Usable like: `unique_callback<int, float>`
-template <typename... Args>
-using unique_callback = typename detail::unique_trait_of<
-  Args...
->::callback;
-
 // TODO channel
 // TODO sink
 
diff --git a/test/playground/test-playground.cpp b/test/playground/test-playground.cpp
index e15ee6d..4c78fb6 100644
--- a/test/playground/test-playground.cpp
+++ b/test/playground/test-playground.cpp
@@ -35,9 +35,7 @@ static cti::continuable<std::string> http_request(std::string url) {
   };
 }
 
-/*
- // TODO Fix this
-static cti::continuable<std::string> http_request(std::string url) {
+static cti::continuable<std::string> http_request3(std::string url) {
   return [url = std::move(url)](auto promise) {
     if (false) {
       promise.set_value("");
@@ -46,7 +44,6 @@ static cti::continuable<std::string> http_request(std::string url) {
     promise.set_exception(std::error_condition{});
   };
 }
-*/
 
 static auto http_request2(std::string url) {
   return cti::make_continuable<std::string>(
@@ -101,5 +98,13 @@ int main(int, char**) {
         // ...
       });
 
+  (http_request("github.com") >> http_request("github.com"))
+      .then([](std::string, std::string) {
+        // ...
+      })
+      .fail([](std::error_condition) {
+        // ...
+      });
+
   return 0;
 }