Update 4.md

docs/examples/4.md

 # Progress Indicator
 
-This example show a graphical composant implemented in OpenGL that would not be easy to implement with raw RN components.
-
-> N.B. the pie is transparent and the background is black with 50% opacity. That would easily allow to put this view on top of an image to show an image upload progress.
+This example shows a graphical component implemented in OpenGL that would not be easy to implement with raw RN components.
 
 ```html
 <PieProgress width={256} height={180} progress={progress} />
@@ -10,6 +8,7 @@ This example show a graphical composant implemented in OpenGL that would not be
 
 ![](4.gif)
 
+> N.B. the pie is transparent and the background is black with 50% opacity (the colors are passed by props). That would easily allow to put this view on top of an image to show an image upload progress.
 
 *explicit props:*