diff --git a/Assets/Scripts/Domain/Model.cs b/Assets/Scripts/Domain/Model.cs
index 2c4da88..0ca7ba3 100644
--- a/Assets/Scripts/Domain/Model.cs
+++ b/Assets/Scripts/Domain/Model.cs
@@ -3,26 +3,31 @@
 		public int Score { private set; get; }
 
 		public readonly int SpawnRate;
-		private bool _needsToSpawn;
+		public readonly int GrowIterations;
 
-		public Model(int spawnRate) : this(0, spawnRate) { }
+		public float GrowPercentage { private set; get; }
 
-		public Model(int score, int spawnRate) {
+		public bool NeedsToSpawn { private set; get; }
+		public bool NeedsToAnimate { private set; get; }
+
+		public Model(int spawnRate, int growIterations) : this(0, spawnRate, growIterations) { }
+
+		public Model(int score, int spawnRate, int growIterations) {
 			Score = score;
 			SpawnRate = spawnRate;
+			GrowIterations = growIterations;
 		}
 
 		public void AddScore() {
 			Score++;
-			if (Score % SpawnRate == 0)
-				_needsToSpawn = true;
-		}
+			NeedsToAnimate = NeedsToSpawn = false;
 
-		public bool NeedsToSpawn() {
-			bool needs = _needsToSpawn;
-			_needsToSpawn = false;
-
-			return needs;
+			if (Score % GrowIterations == 0) {
+				GrowPercentage = Score / (float)(SpawnRate * GrowIterations);
+				NeedsToAnimate = true;
+			}
+			if (Score % (SpawnRate * GrowIterations) == 0)
+				NeedsToSpawn = true;
 		}
 	}
 }
\ No newline at end of file
diff --git a/Assets/Scripts/Presenter/ExpressionClick.cs b/Assets/Scripts/Presenter/ExpressionClick.cs
index 6b2dba9..24c08bd 100644
--- a/Assets/Scripts/Presenter/ExpressionClick.cs
+++ b/Assets/Scripts/Presenter/ExpressionClick.cs
@@ -16,7 +16,7 @@ namespace Presenter {
 			_model.AddScore();
 			_view.UpdateView(_model.Score);
 
-			if (_model.NeedsToSpawn()) {
+			if (_model.NeedsToSpawn) {
 				_spawner.SpawnRose();
 			}
 		}
diff --git a/Assets/Scripts/Tests/ModelTests.cs b/Assets/Scripts/Tests/ModelTests.cs
new file mode 100644
index 0000000..afe1df4
--- /dev/null
+++ b/Assets/Scripts/Tests/ModelTests.cs
@@ -0,0 +1,93 @@
+using Domain;
+using NUnit.Framework;
+
+namespace Tests {
+	public class ModelTests {
+		[Test]
+		public void NoPress_NoAnimation() {
+			Model sut = new(20, 5);
+
+			Assert.IsFalse(sut.NeedsToAnimate);
+		}
+
+		[Test]
+		public void NotEnoughPresses_NoAnimation() {
+			Model sut = new(20, 5);
+
+			sut.AddScore();
+
+			Assert.IsFalse(sut.NeedsToAnimate);
+		}
+
+
+		[Test]
+		public void EnoughPresses_Animation() {
+			Model sut = new(20, 5);
+
+			for (int i = 0; i < 5; i++)
+				sut.AddScore();
+
+			Assert.IsTrue(sut.NeedsToAnimate);
+		}
+
+		[Test]
+		public void NoPress_NoSpawn() {
+			Model sut = new(20, 5);
+
+			Assert.IsFalse(sut.NeedsToSpawn);
+		}
+
+		[Test]
+		public void NotEnoughPresses_NoSpawn() {
+			Model sut = new(20, 5);
+
+			sut.AddScore();
+
+			Assert.IsFalse(sut.NeedsToSpawn);
+		}
+
+		[Test]
+		public void EnoughPresses_Spawn() {
+			Model sut = new(20, 5);
+
+			for (int i = 0; i < 20 * 5; i++) {
+				sut.AddScore();
+			}
+
+			Assert.IsTrue(sut.NeedsToSpawn);
+		}
+
+		[Test]
+		public void OneIteration_UpdatesGrowPercentage() {
+			Model sut = new(5, 5);
+
+			for (int i = 0; i < 5; i++) {
+				sut.AddScore();
+			}
+
+			Assert.AreEqual(1f / 5f, sut.GrowPercentage);
+		}
+
+		[Test]
+		public void AllIterations_GrowCompleted() {
+			Model sut = new(5, 5);
+
+			for (int i = 0; i < 5 * 5; i++) {
+				sut.AddScore();
+			}
+
+			Assert.AreEqual(1f, sut.GrowPercentage);
+		}
+
+		[Test]
+		public void MoreIterations_ResetsGrowPercentage() {
+			Model sut = new(5, 5);
+
+			for (int i = 0; i < 6 * 5; i++) {
+				sut.AddScore();
+			}
+
+			Assert.AreEqual(1f / 5f, sut.GrowPercentage);
+		}
+	}
+}
\ No newline at end of file
diff --git a/Assets/Scripts/Tests/ModelTests.cs.meta b/Assets/Scripts/Tests/ModelTests.cs.meta
new file mode 100644
index 0000000..2b507ba
--- /dev/null
+++ b/Assets/Scripts/Tests/ModelTests.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: b81eb0f05b9b4ed38c6b881421132fdd
+timeCreated: 1713269019
\ No newline at end of file
diff --git a/Assets/Scripts/View/Dependencies.cs b/Assets/Scripts/View/Dependencies.cs
index 46a0181..eb24ae0 100644
--- a/Assets/Scripts/View/Dependencies.cs
+++ b/Assets/Scripts/View/Dependencies.cs
@@ -11,7 +11,7 @@ namespace View {
 		public CustomInput CustomInput { private set; get; }
 
 		private void Awake() {
-			Model = new Model(20);
+			Model = new Model(20, 5);
 
 			IExpressionInput input = FindObjectOfType<ExpressionInput>();
 			IExpressionInput visibility = FindObjectOfType<UIVisibility>();