diff --git a/README.md b/README.md
index fafe484..de5d112 100644
--- a/README.md
+++ b/README.md
@@ -19,11 +19,8 @@ The class `xApplication` is a singleton representing your application, its windo
 
 The interface `xElement` represents any graphical feature to be drawn on the screen. Any number of `xElement` can be pushed to or pulled from the application at any time in order to show them or not.
 
+The interface `xOrchestrable` represents any class that can be called during the application scheduling. Any number of `xOrchestrable` can be added or removed from the application at any time in order to execute them or not.
+
 The class `xSprite` represents a sprite that can is a rectangle that can draw either as a single color, an image, or a copy of another sprite. It can be moved over time. Also, it allows you to set a custom clip if this is an image sprite.
 
-The class `xSpriteAnimation` derives from an image sprite, which clip can change over time. These clips are called _frames_ and have to be set beforehand, when ready you can start or stop the animation with a specified delay between frames. Every `xSpriteAnimation` is scheduled on the same dedicated animation thread.
-
-
-The concurrency model is led simple :
-- the main loop schedules rendering and user input
-- the animation loop schedules animation frame shifts
+The class `xSpriteAnimation` derives from an image sprite, which clip can change over time. These clips are called _frames_ and have to be set beforehand. It is also an orchestrable (i.e. animates on application ticks), you can start or stop the animation with a specified time interval. Every `xSpriteAnimation` is scheduled by the `xApplication`.