added density

code improvements

Scripts/Elements/Element.cs

@@ -6,6 +6,7 @@ public class Element {
     public Color Color = Colors.Black;
 
     public Vector2I Position;
+    public int Density;
 
     protected readonly float MaxColorVariance = 0.1f;
     protected readonly Level Level;
@@ -40,9 +41,7 @@ public class Element {
     }
 
     protected virtual void Tick() {
-        int randomDirection = 1;
-        if (GD.Randi() % 2 != 0)
-            randomDirection *= -1;
+        int randomDirection = GD.Randi() % 2 != 0 ? 1 : -1;
 
         if (Level.IsEmpty(Position + Vector2I.Down)) {
             Level.Swap(this, Position + Vector2I.Down);
@@ -53,6 +52,15 @@ public class Element {
         } else if (Level.IsEmpty(Position + Vector2I.Down + Vector2I.Right * randomDirection * -1)) {
             Level.Swap(this, Position + Vector2I.Right*randomDirection);
         }
+
+        if (GD.Randi() % 10 > 1) return; // ascend slower
+
+        if (Level.Get(Position + Vector2I.Down
+                               // maybe also side
+                               + (GD.Randi() % 2 != 0 ?
+                                   Vector2I.Zero : Vector2I.Right * randomDirection)
+            )?.Density < Density)
+            Level.Swap(this, Position + Vector2I.Down);
     }
 
     protected Color AddColorVariance(Color baseColor) {