diff --git a/Diya/Diya2DNode.class.st b/Diya/Diya2DNode.class.st
index d9b3026..27c4682 100644
--- a/Diya/Diya2DNode.class.st
+++ b/Diya/Diya2DNode.class.st
@@ -77,11 +77,22 @@ Diya2DNode >> recFromBuffer [
 Diya2DNode >> updateTF [
 	tf := MatrixTransform2x3 identity.
 	"translation"
-	tf setOffset: translation.
+	tf setOffset: translation + pivot.
 	"rotation"
 	rotation = 0 ifFalse:[tf setAngle: rotation ].
-	"scale"
-	tf setScale: scale.
+	"translate back to pivot"
+	pivot isZero ifFalse:[
+		tf := tf composedWithLocal:
+			(MatrixTransform2x3 identity
+				setOffset: pivot negated;
+				yourself)
+	].
+	scale isZero ifFalse: [
+		tf := tf composedWithLocal:
+			(MatrixTransform2x3 identity
+				setScale: scale;
+				yourself)
+	].
 	self parent ifNil: [ ^self ].
 	self parent isRoot ifFalse: [tf := self parent tf composedWithLocal:  tf ].
 	children ifNotNil: [children do:[:c| c updateTF ]].
diff --git a/Diya/Diya2DPrimShape.class.st b/Diya/Diya2DPrimShape.class.st
index c5b187d..0635422 100644
--- a/Diya/Diya2DPrimShape.class.st
+++ b/Diya/Diya2DPrimShape.class.st
@@ -75,7 +75,6 @@ Diya2DPrimShape >> extent [
 Diya2DPrimShape >> initialize [
 	super initialize.
 	texture := nil.
-	children := nil.
 	type := GL_TRIANGLES.
 	bbox := Rectangle origin: 0@0 corner: 0@0.
 ]
diff --git a/Diya/DiyaApplicationLauncher.class.st b/Diya/DiyaApplicationLauncher.class.st
index 4349f65..84ef12b 100644
--- a/Diya/DiyaApplicationLauncher.class.st
+++ b/Diya/DiyaApplicationLauncher.class.st
@@ -47,9 +47,11 @@ DiyaApplicationLauncher >> launch: app [
 		root empty.
 	].
 	currapp := app uniqueInstance.
-	self appNode addNode: currapp root.
+	currapp setup.
+	currapp root forceReload.
+	Transcript show: 'APPLICATION INIT'; cr.
 	self context assets: currapp am.
-	currapp setup
+	self appNode addNode: currapp root.
 ]
 
 { #category : #initialization }
@@ -64,7 +66,7 @@ DiyaApplicationLauncher >> main [
 	].
 	currapp ifNotNil: [currapp main.].
 	"root render."
-	[ root stepDown  ] fork.
+	root stepDown.
 	self process.
 	root render.
 ]
@@ -73,11 +75,12 @@ DiyaApplicationLauncher >> main [
 DiyaApplicationLauncher >> process [
 	|Q  node maxProcessingTime|
 	maxProcessingTime := 1000 / DiyaBoot maxFPS - 100.
-	Q := DiyaRendererContext uniqueInstance processQueue.
+	Q := root processingQueue select:[:e| e visibility].
 	Q ifEmpty:[^ self].
 	[
 		node := Q removeFirst.
 		node process.
+		root cleanDirtyNode: node.
 	 	Q isNotEmpty and: DiyaClock uniqueInstance lapDelta asMilliSeconds < maxProcessingTime
 	] whileTrue
 	
@@ -102,7 +105,7 @@ DiyaApplicationLauncher >> setup [
 			#bgColor -> Color orange.
 			#border -> 3
 		}.
-	root addNode: (Diya2DNode new) at: 0@0.
+	root addNode: (DiyaCompositeNode new) at: 0@0.
 	txtFPS := root addNode:(DiyaText data: '') at: ( self context resolution x - 80)@(self context resolution y - 40).
 	txtFPS extent: 80@40.
 	txtFPS styleName: #fps_text.
diff --git a/Diya/DiyaBaseApplication.class.st b/Diya/DiyaBaseApplication.class.st
index 68d9a88..13789c6 100644
--- a/Diya/DiyaBaseApplication.class.st
+++ b/Diya/DiyaBaseApplication.class.st
@@ -7,6 +7,7 @@ Class {
 { #category : #initialization }
 DiyaBaseApplication >> initialize [
 	super initialize.
-	root := Diya2DNode new.
+	root := DiyaCompositeNode new.
+	root styleName: #global.
 	am := AssetManager new.
 ]
diff --git a/Diya/DiyaCompositeNode.class.st b/Diya/DiyaCompositeNode.class.st
new file mode 100644
index 0000000..a09521f
--- /dev/null
+++ b/Diya/DiyaCompositeNode.class.st
@@ -0,0 +1,22 @@
+Class {
+	#name : #DiyaCompositeNode,
+	#superclass : #Diya2DNode,
+	#category : #'Diya-Graphics'
+}
+
+{ #category : #accessing }
+DiyaCompositeNode >> process [
+	
+]
+
+{ #category : #accessing }
+DiyaCompositeNode >> setClean [
+	
+	
+]
+
+{ #category : #accessing }
+DiyaCompositeNode >> setDirty [
+	
+	
+]
diff --git a/Diya/DiyaEllipse.class.st b/Diya/DiyaEllipse.class.st
index b3ba463..37c3304 100644
--- a/Diya/DiyaEllipse.class.st
+++ b/Diya/DiyaEllipse.class.st
@@ -92,6 +92,6 @@ DiyaEllipse >> setUpShader [
 	self shader
 		setUniform: #u_border value: (self ? #border);
 		setUniform: #u_border_color value: ( self ? #borderColor) asGL4FArray;
-		setUniform: #u_rx value: rx;
-		setUniform: #u_ry value: ry.
+		setUniform: #u_rx value: (rx * (scale x)) ;
+		setUniform: #u_ry value: (ry * (scale y)) .
 ]
diff --git a/Diya/DiyaExampleApp.class.st b/Diya/DiyaExampleApp.class.st
index 3459eae..4f3795b 100644
--- a/Diya/DiyaExampleApp.class.st
+++ b/Diya/DiyaExampleApp.class.st
@@ -89,7 +89,7 @@ DiyaExampleApp >> setup [
 	node1 rotation: 45.
 	node1 scale: 2.0@2.0.
 	node1 on: #(mousebuttondown fingerdown) do:[:e|
-		label txt: 'Mouse ', (node1 local: e mapped worldPosition) asIntegerPoint asString].
+		label txt: 'RECT ', (node1 local: e mapped worldPosition) asIntegerPoint asString].
 	
 	img := root addNode: (DiyaImageView from:'mrsang.png') at: 10 @ 400.
 	img styleName: #image_view.
@@ -117,15 +117,17 @@ DiyaExampleApp >> setup [
 	node := root addNode: (DiyaLine from: 10@10 to: 200@200).
 	node styleName: #line_view.
 		
-	ell := root addNode: (DiyaEllipse rx:100  ry: 70) at: 100@300.
-	ell rotation: 30.
+	ell := root addNode: (DiyaEllipse rx:100  ry: 70) at: 120@300.
+	ell scale: 1.2 @ 1.2.
 	ell styleName: #ell_view.
-	"node rotation: Float pi / 2.0."
 	ell textureNamed:'mrsang.png'.
+	ell addNode: (DiyaTimerNode timeout: 1000 / 6 do:[:n |
+		n parent rotation: n parent rotation + 10.	
+	] ).
 	ell on: #(mousebuttondown fingerdown) do:[:e|
 		label txt: 'Ellipse clicked', (ell local:e mapped worldPosition) asIntegerPoint asString].
 
-	node := root addNode: (DiyaConvexPolygon points:{250@100. 400@250. 450@80. 350@60}).
+	node := root addNode: (DiyaConvexPolygon points:{0@40. 150@190. 200@20. 100@0}) at: 250@60.
 	node textureNamed: 'mrsang.png'.
 	node styleName: #poly_view.
 	
@@ -133,8 +135,13 @@ DiyaExampleApp >> setup [
 	icon styleName: #text_icon_2.
 	
 	button := root addNode: (DiyaButton text: 'Click me !') at: 240@460.
+	icon := DiyaFontIcon data: 16rF130.
+	"icon := DiyaImageIcon from:  'mrsang.png'."
+	icon addNode:(DiyaTimerNode timeout: 1000 / 12 do:[:n |
+		n parent rotation: n parent rotation + 10 pivot: n parent extent / 2.	
+	] ).
 	button extent: 200@40.
-	button icon:16rF185"'mrsang.png'".
+	button icon: icon "'mrsang.png'".
 	"button rotation: Float pi / 2.0."
 	button styleName: #button_view.
 	Transcript show: 'Application setup';cr.
diff --git a/Diya/DiyaLabel.class.st b/Diya/DiyaLabel.class.st
index 3c0184d..7b16f9e 100644
--- a/Diya/DiyaLabel.class.st
+++ b/Diya/DiyaLabel.class.st
@@ -32,7 +32,7 @@ DiyaLabel >> icon: anObject [
 	anObject isString ifTrue: [
 		icon := self addNode: (DiyaImageIcon from: anObject).
 	].
-	icon ifNil: [ ^ DiyaCoreAPIError signal: 'Invalid icon identification'].
+	icon ifNil: [ icon := self addNode: anObject ].
 	self setDirty
 ]
 
diff --git a/Diya/DiyaMetaNode.class.st b/Diya/DiyaMetaNode.class.st
new file mode 100644
index 0000000..f30b8ff
--- /dev/null
+++ b/Diya/DiyaMetaNode.class.st
@@ -0,0 +1,40 @@
+Class {
+	#name : #DiyaMetaNode,
+	#superclass : #DiyaNode,
+	#category : #'Diya-Graphics'
+}
+
+{ #category : #accessing }
+DiyaMetaNode >> addNode: node at: pos [
+	self shouldNotBeCalled
+]
+
+{ #category : #accessing }
+DiyaMetaNode >> boundingBox [
+	^ 0@0
+]
+
+{ #category : #rendering }
+DiyaMetaNode >> draw [
+	
+]
+
+{ #category : #accessing }
+DiyaMetaNode >> extent [
+	^  0@0
+]
+
+{ #category : #testing }
+DiyaMetaNode >> inner: aPoint [
+	^ false
+]
+
+{ #category : #processing }
+DiyaMetaNode >> process [
+	
+]
+
+{ #category : #processing }
+DiyaMetaNode >> updateTF [
+	
+]
diff --git a/Diya/DiyaNode.class.st b/Diya/DiyaNode.class.st
index 3fcf07b..77bf113 100644
--- a/Diya/DiyaNode.class.st
+++ b/Diya/DiyaNode.class.st
@@ -14,7 +14,9 @@ Class {
 		'root',
 		'styleName',
 		'style',
-		'id'
+		'id',
+		'visibility',
+		'pivot'
 	],
 	#pools : [
 		'OpenGLConstants',
@@ -53,25 +55,13 @@ DiyaNode >> addNode: node [
 DiyaNode >> addNode: node at: pos [
 	children ifNil: [ ^self ].
 	node parent: self.
-	node position: pos.
 	children add: node.
+	node position: pos.
 	node root: self root.
+	node setDirtyAll.
 	^ node 
 ]
 
-{ #category : #accessing }
-DiyaNode >> allChildren [
-	|nodes|
-	nodes := OrderedCollection new.
-	children ifNil: [ ^ nodes ].
-	children do:[:c|
-		nodes add: c.
-		c allChildren do:[:e| nodes add:e].
-	].
-	^nodes
-	
-]
-
 { #category : #accessing }
 DiyaNode >> boundingBox [
 	^ self subclassResponsibility 
@@ -82,7 +72,7 @@ DiyaNode >> children [
 	^children
 ]
 
-{ #category : #accessing }
+{ #category : #rendering }
 DiyaNode >> draw [
 	self subclassResponsibility 
 ]
@@ -97,6 +87,15 @@ DiyaNode >> extent [
 	^  self subclassResponsibility  
 ]
 
+{ #category : #processing }
+DiyaNode >> forceReload [
+	self process.
+	children ifNotNil: [
+	children do:[:c|
+		c forceReload
+	]]
+]
+
 { #category : #accessing }
 DiyaNode >> id [
 	^ id
@@ -113,10 +112,12 @@ DiyaNode >> initialize [
 	styleName := nil.
 	style := nil.
 	root := nil.
+	visibility := true.
+	pivot := 0@0.
 	id := self className,'#',(Random new nextInt: 1e6) asString.
 ]
 
-{ #category : #accessing }
+{ #category : #testing }
 DiyaNode >> inner: aPoint [
 	^ self subclassResponsibility 
 ]
@@ -143,6 +144,11 @@ DiyaNode >> parent: anObject [
 	parent := anObject
 ]
 
+{ #category : #accessing }
+DiyaNode >> pivot [
+	^ pivot
+]
+
 { #category : #accessing }
 DiyaNode >> position [
 	^ translation
@@ -154,7 +160,7 @@ DiyaNode >> position: anObject [
 	self updateTF.
 ]
 
-{ #category : #accessing }
+{ #category : #processing }
 DiyaNode >> process [
 	^self subclassResponsibility 
 ]
@@ -163,13 +169,26 @@ DiyaNode >> process [
 DiyaNode >> register: aBlock to: eventName [
 	|evtCode|
 	evtCode := SDL2Constants bindingOf: ('SDL_', eventName asUppercase).
-	evtCode ifNil: [ ^DiyaCoreAPIError signal: 'Unknow event ', eventName ].
+	evtCode ifNil: [ evtCode := eventName  ].
 	ehandlers at: evtCode value put: aBlock.
 	
 ]
 
-{ #category : #accessing }
+{ #category : #removing }
+DiyaNode >> remove [
+	self setClean.
+	root := nil.
+	parent ifNotNil: [ parent removeChild: self ]
+]
+
+{ #category : #removing }
+DiyaNode >> removeChild: c [
+	children ifNotNil: [ children remove: c ifAbsent:[  ]]
+]
+
+{ #category : #rendering }
 DiyaNode >> render [
+	visibility ifFalse:[^self].
 	shader ifNotNil: [self setUpShader].
 	self draw.
 	children ifNil: [ ^self ].
@@ -201,6 +220,13 @@ DiyaNode >> rotation: anObject [
 	self updateTF.
 ]
 
+{ #category : #accessing }
+DiyaNode >> rotation: anObject pivot: p [
+	rotation := anObject.
+	pivot := p.
+	self updateTF.
+]
+
 { #category : #accessing }
 DiyaNode >> scale [
 	^ scale
@@ -212,21 +238,26 @@ DiyaNode >> scale: anObject [
 	self updateTF.
 ]
 
-{ #category : #initialization }
+{ #category : #'changing state' }
 DiyaNode >> setClean [
-	|Q|
-	Q := DiyaRendererContext uniqueInstance processQueue.
-	Q remove: self ifAbsent: [  ]
+	 root ifNil: [ ^self ].
+	root cleanDirtyNode: self.
 ]
 
-{ #category : #initialization }
+{ #category : #'changing state' }
 DiyaNode >> setDirty [
-	|Q|
-	Q := DiyaRendererContext uniqueInstance processQueue.
-	(Q includes: self ) ifFalse:[ Q add: self].
+	root ifNil: [ ^self ].
+	self root enqueueDirtyNode: self.
 ]
 
-{ #category : #accessing }
+{ #category : #'changing state' }
+DiyaNode >> setDirtyAll [
+	self setDirty.
+	children ifNotNil: [
+		children do:[:c| c setDirtyAll] ]
+]
+
+{ #category : #rendering }
 DiyaNode >> setUpShader [
 	|mem|
 		mem := self tf asGLBuffer.
@@ -264,7 +295,7 @@ DiyaNode >> step [
 
 { #category : #stepping }
 DiyaNode >> stepDown [
-	self step
+	self step.
 	children ifNotNil: [ children do:[:c | c stepDown ] ]
 ]
 
@@ -303,7 +334,17 @@ DiyaNode >> trigger: evt [
 	].
 ]
 
-{ #category : #accessing }
+{ #category : #processing }
 DiyaNode >> updateTF [
 	self subclassResponsibility 
 ]
+
+{ #category : #accessing }
+DiyaNode >> visibility [
+	^ visibility
+]
+
+{ #category : #accessing }
+DiyaNode >> visibility: anObject [
+	visibility := anObject
+]
diff --git a/Diya/DiyaPolygon.class.st b/Diya/DiyaPolygon.class.st
index f4b4cb6..fd9cb43 100644
--- a/Diya/DiyaPolygon.class.st
+++ b/Diya/DiyaPolygon.class.st
@@ -42,9 +42,6 @@ DiyaPolygon >> points: anObject [
 
 { #category : #accessing }
 DiyaPolygon >> process [
-	bbox := self recFromPoints.
-	translation = bbox origin ifFalse:[ self position: bbox origin].
-	points := points collect:[:e | e - bbox origin].
 	bbox := self recFromPoints.
 	self calculateVertices.
 	^true
diff --git a/Diya/DiyaRendererContext.class.st b/Diya/DiyaRendererContext.class.st
index ccc2bab..414b990 100644
--- a/Diya/DiyaRendererContext.class.st
+++ b/Diya/DiyaRendererContext.class.st
@@ -9,8 +9,7 @@ Class {
 		'texture0',
 		'projection',
 		'assets',
-		'window',
-		'rqueue'
+		'window'
 	],
 	#pools : [
 		'OpenGLConstants',
@@ -67,7 +66,6 @@ DiyaRendererContext >> initialize [
 	vbo bind: GL_ARRAY_BUFFER.
 	projection := Array2D identity: 4.
 	assets := AssetManager new.
-	rqueue := OrderedCollection new.
 ]
 
 { #category : #accessing }
@@ -80,11 +78,6 @@ DiyaRendererContext >> mouse: anObject [
 	mouse := anObject
 ]
 
-{ #category : #accessing }
-DiyaRendererContext >> processQueue [
-	^ rqueue
-]
-
 { #category : #accessing }
 DiyaRendererContext >> projection [
 	^ projection
diff --git a/Diya/DiyaRootNode.class.st b/Diya/DiyaRootNode.class.st
index d526dff..e4004ae 100644
--- a/Diya/DiyaRootNode.class.st
+++ b/Diya/DiyaRootNode.class.st
@@ -12,16 +12,16 @@ DiyaRootNode >> Q [
 	^ Q
 ]
 
-{ #category : #accessing }
-DiyaRootNode >> Q: v [
-	Q := v
-]
-
 { #category : #accessing }
 DiyaRootNode >> boundingBox [
 	^ Rectangle origin: 0@0 corner: context resolution 
 ]
 
+{ #category : #'add/remove' }
+DiyaRootNode >> cleanDirtyNode: aNode [
+	Q remove: aNode ifAbsent:[]
+]
+
 { #category : #accessing }
 DiyaRootNode >> draw [
 	|c|
@@ -31,6 +31,11 @@ DiyaRootNode >> draw [
 	context vbo bind: GL_ARRAY_BUFFER.
 ]
 
+{ #category : #'add/remove' }
+DiyaRootNode >> enqueueDirtyNode: aNode [
+	(Q includes: aNode ) ifFalse:[ Q add: aNode].
+]
+
 { #category : #accessing }
 DiyaRootNode >> extent [
 	^  context resolution 
@@ -58,7 +63,7 @@ DiyaRootNode >> isRoot [
 
 { #category : #initialization }
 DiyaRootNode >> process [
-	^true
+	
 ]
 
 { #category : #accessing }
@@ -66,6 +71,19 @@ DiyaRootNode >> processingQueue [
 	^ Q
 ]
 
+{ #category : #initialization }
+DiyaRootNode >> setClean [
+	
+	
+	
+]
+
+{ #category : #initialization }
+DiyaRootNode >> setDirty [
+	
+	
+]
+
 { #category : #accessing }
 DiyaRootNode >> updateTF [
 	"donothing"
diff --git a/Diya/DiyaTimerNode.class.st b/Diya/DiyaTimerNode.class.st
new file mode 100644
index 0000000..7f42ef8
--- /dev/null
+++ b/Diya/DiyaTimerNode.class.st
@@ -0,0 +1,68 @@
+Class {
+	#name : #DiyaTimerNode,
+	#superclass : #DiyaMetaNode,
+	#instVars : [
+		'timeout',
+		'elapsedTime',
+		'handlers'
+	],
+	#category : #'Diya-Graphics'
+}
+
+{ #category : #accessing }
+DiyaTimerNode class >> timeout: ms [
+	^ self new timeout: ms; yourself
+]
+
+{ #category : #accessing }
+DiyaTimerNode class >> timeout: ms do: aBlock [
+	^ (self timeout: ms) onTimeout: aBlock;yourself
+]
+
+{ #category : #accessing }
+DiyaTimerNode class >> timeout: ms doOnce: aBlock [
+	^ (self timeout: ms) onceTimeout:  aBlock;yourself
+]
+
+{ #category : #accessing }
+DiyaTimerNode >> delta [
+	^ DiyaClock uniqueInstance delta asMilliSeconds
+]
+
+{ #category : #accessing }
+DiyaTimerNode >> initialize [
+	super initialize.
+	elapsedTime := 0.
+	handlers := OrderedCollection new.
+]
+
+{ #category : #'as yet unclassified' }
+DiyaTimerNode >> onTimeout: aBlock [
+	handlers add: aBlock
+]
+
+{ #category : #'as yet unclassified' }
+DiyaTimerNode >> onceTimeout: aBlock [
+	|newBlock|
+	handlers := OrderedCollection new.
+	newBlock := [ :node | aBlock value: node. self remove ].
+	handlers add: newBlock
+]
+
+{ #category : #stepping }
+DiyaTimerNode >> step [
+	elapsedTime := elapsedTime + self delta.
+	elapsedTime >= timeout ifFalse:[^ self].
+	handlers do:[:e| e value: self ].
+	elapsedTime := 0
+]
+
+{ #category : #accessing }
+DiyaTimerNode >> timeout [
+	^ timeout
+]
+
+{ #category : #accessing }
+DiyaTimerNode >> timeout: anObject [
+	timeout := anObject
+]