diff --git a/src/core/Gauge.scala b/src/core/Gauge.scala
index b3e471c..dbd1186 100644
--- a/src/core/Gauge.scala
+++ b/src/core/Gauge.scala
@@ -17,8 +17,3 @@ object Gauge:
   type BeatPerMinute = BeatPerMinute.type
   type StepPerMinute = StepPerMinute.type
   type Pace          = Pace.type
-
-trait Distance
-trait Duration
-trait Timestamp
-trait Box
diff --git a/src/core/Page.scala b/src/core/Page.scala
new file mode 100644
index 0000000..bdaa58f
--- /dev/null
+++ b/src/core/Page.scala
@@ -0,0 +1,13 @@
+package core
+
+
+trait Page[A] extends (Mutation => Option[Mutation])
+
+object Page:
+  given any: Page[EmptyTuple] = Some(_)
+
+  given tuple[H, T <: Tuple](using h: Page[H], t: Page[T]): Page[H *: T] =
+    a => h(a).flatMap(t)
+
+  def apply[A](using pa: Page[A]) = pa
+end Page
\ No newline at end of file
diff --git a/src/core/package.scala b/src/core/package.scala
index 390702c..ee9ca32 100644
--- a/src/core/package.scala
+++ b/src/core/package.scala
@@ -10,15 +10,10 @@ extension [A](a: A) inline def single: NonEmpty[A] = a -> List.empty[A]
 type Interval[A] = NonEmpty[A]
 type History[A]  = NonEmpty[Interval[A]]
 
-trait Page[A] extends (Mutation => Option[Mutation])
-object Page:
-  given any: Page[EmptyTuple] = Some(_)
-
-  given tuple[H, T <: Tuple](using h: Page[H], t: Page[T]): Page[H *: T] =
-    a => h(a).flatMap(t)
-
-  def apply[A](using pa: Page[A]) = pa
-end Page
+sealed trait Distance
+sealed trait Duration
+sealed trait Timestamp
+sealed trait Box
 
 type Injection[A] = (HTMLElement, A)
 trait Inject[A] extends (Injection[A] => Unit):