diff --git a/main.go b/main.go
index f6e8866..fc005d6 100644
--- a/main.go
+++ b/main.go
@@ -20,15 +20,15 @@ const (
 )
 
 type TextureCam struct {
-	SourceWidth int
+	SourceWidth  int
 	SourceHeight int
-	LookAt rl.Vector2
-	Zoom float32
+	LookAt       rl.Vector2
+	Zoom         float32
 }
 
 func main() {
 
-	sourceWidth  := sourceScale * targetWidth
+	sourceWidth := sourceScale * targetWidth
 	sourceHeight := sourceScale * targetHeight
 
 	os.MkdirAll(snapshotsDir, 0755)
@@ -44,10 +44,10 @@ func main() {
 
 	// point at source center
 	// put source center at center of screen
-	var camera = TextureCam {
-		LookAt: rl.Vector2 { X: float32(sourceWidth) / 2.0, Y: float32(sourceHeight) / 2.0 },
-		Zoom: 1.0,
-		SourceWidth: sourceWidth,
+	var camera = TextureCam{
+		LookAt:       rl.Vector2{X: float32(sourceWidth) / 2.0, Y: float32(sourceHeight) / 2.0},
+		Zoom:         1.0,
+		SourceWidth:  sourceWidth,
 		SourceHeight: sourceHeight,
 	}
 
@@ -55,19 +55,19 @@ func main() {
 	t0 := time.Now()
 
 	/*
-	*/
+	 */
 
 	imageField := NewImageField("/home/d/Dropbox/art/passage/data/david.png")
 
 	field :=
 		TranslateField{
-				x: -float32(sourceWidth/2.0),
-				y: -float32(sourceHeight/2.0),
-				field: &ScaleField {
-					scale: 5.0,
-					field: &imageField,
-				},
-			}
+			x: -float32(sourceWidth / 2.0),
+			y: -float32(sourceHeight / 2.0),
+			field: &ScaleField{
+				scale: 5.0,
+				field: &imageField,
+			},
+		}
 	rng := rand.New(rand.NewSource(0))
 
 	contourLayer := NewContourLayer(rng, &field, sourceWidth, sourceHeight)
@@ -75,11 +75,11 @@ func main() {
 	sketch := NewSketch()
 	//sketch.CreateLayer("testPattern", &TestPattern{}, int32(sourceWidth), int32(sourceHeight))
 	//sketch.CreateLayer("actors", &contourLayer, int32(sourceWidth), int32(sourceHeight))
-	sketch.CreateLayer("field", &FieldLayer { field: &field, dirty: true }, int32(sourceWidth), int32(sourceHeight))
+	sketch.CreateLayer("field", &FieldLayer{field: &field, dirty: true}, int32(sourceWidth), int32(sourceHeight))
 	sketch.CreateLayer("contours", &contourLayer, int32(sourceWidth), int32(sourceHeight))
 
 	ports := MakePorts()
-	ports["sierpinskiArrowAngle"] = Sine {
+	ports["sierpinskiArrowAngle"] = Sine{
 		Amp:  120,
 		Bias: 100,
 		Freq: 0.1,
@@ -110,7 +110,7 @@ func main() {
 		rl.ClearBackground(rl.Blank)
 
 		sketch.Draw(renderCtx)
- 
+
 		if rl.IsKeyDown(rl.KeySpace) {
 			if _, err := storage.Save(); err != nil {
 				log.Printf("Error saving snapshot: %v\n", err)
@@ -126,7 +126,7 @@ func main() {
 			if c == 'c' {
 				resetCamera(&camera)
 			} else if c >= '1' && c <= '9' {
-				zoom := 1 << int(ch - '0')
+				zoom := 1 << int(ch-'0')
 				camera.Zoom = float32(zoom)
 			}
 		}
@@ -140,7 +140,7 @@ func main() {
 }
 
 func resetCamera(cam *TextureCam) {
-	cam.LookAt = rl.Vector2 { X: float32(cam.SourceWidth) / 2.0, Y: float32(cam.SourceHeight) / 2.0 }
+	cam.LookAt = rl.Vector2{X: float32(cam.SourceWidth) / 2.0, Y: float32(cam.SourceHeight) / 2.0}
 	cam.Zoom = 1.0
 }
 
@@ -150,7 +150,7 @@ type FieldLayer struct {
 }
 
 func (s *FieldLayer) Update(ctx *RenderCtx) {
-	;
+
 }
 
 func (s *FieldLayer) Draw(ctx *RenderCtx) {
@@ -169,32 +169,47 @@ func (s *FieldLayer) IsDirty() bool {
 }
 
 type ContourLayer struct {
-	field  Field
-	actors []*Actor
+	field                     Field
+	actors                    []*Actor
+	rng                       *rand.Rand
+	sourceWidth int
+	sourceHeight int
 }
 
 func NewContourLayer(rng *rand.Rand, field Field, sourceWidth int, sourceHeight int) ContourLayer {
 
-	actors := make([]*Actor, 20000)
-	for i := range len(actors) {
-		x := rng.Int() % sourceWidth
-		y := rng.Int() % sourceHeight
-		actors[i] =
-			&Actor{
-				position: rl.Vector2 { X: float32(x), Y: float32(y) },
-				field: field,
+	actors := make([]*Actor, 0)
+
+	layer := ContourLayer {
+		rng: rng,
+		field: field,
+		actors:       actors,
+		sourceWidth:  sourceWidth,
+		sourceHeight: sourceHeight,
+	}
+
+	layer.AddActors(1)
+
+	return layer
+}
+
+func (s *ContourLayer) AddActors(n int) {
+	for range n {
+		x := s.rng.Int() % s.sourceWidth
+		y := s.rng.Int() % s.sourceHeight
+		newActor :=
+			&Actor {
+				position: rl.Vector2{X: float32(x), Y: float32(y)},
+				field:    s.field,
 				stepSize: 1,
 				color:    rl.NewColor(11, 35, 176, 100),
 			}
-	}
-
-	return ContourLayer{
-		actors: actors,
+		s.actors = append(s.actors, newActor)
 	}
 }
 
 func (s *ContourLayer) Update(ctx *RenderCtx) {
-	;
+	s.AddActors(100) // parameterize
 }
 
 func (s *ContourLayer) Draw(ctx *RenderCtx) {