diff --git a/examples/Basic/implementations/Basic.World.cpp b/examples/Basic/implementations/Basic.World.cpp
index 14459f5..eb27403 100644
--- a/examples/Basic/implementations/Basic.World.cpp
+++ b/examples/Basic/implementations/Basic.World.cpp
@@ -16,6 +16,7 @@ void Basic::World::Reset() {
 
 void Basic::World::Clear() {
     balls.clear();
+    nextId = 1;
     time = 0;
     fastest = 0;
 }
diff --git a/examples/Basic/interfaces/Basic.World.cppm b/examples/Basic/interfaces/Basic.World.cppm
index 3ec2b06..892f5c7 100644
--- a/examples/Basic/interfaces/Basic.World.cppm
+++ b/examples/Basic/interfaces/Basic.World.cppm
@@ -43,8 +43,9 @@ export namespace Basic {
         Physics physics;
         Floor floor;
 
-        // Removes every ball and drops the scene's five.
+        // Removes every ball and drops the scene's five, as balls 1 to 5.
         void Reset();
+        // Removes every ball; ids start again from 1.
         void Clear();
         // Returns the new ball's id.
         std::int32_t Spawn(float x, float y, float vy, float radius);