diff --git a/half-earth/nodes/clock.tscn b/half-earth/nodes/clock.tscn
new file mode 100644
index 0000000..7d4c9fe
--- /dev/null
+++ b/half-earth/nodes/clock.tscn
@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=2]
+
+[ext_resource path="res://scripts/Clock.cs" type="Script" id=1]
+
+[node name="Clock" type="Node"]
+script = ExtResource( 1 )
diff --git a/half-earth/nodes/debug_ui.tscn b/half-earth/nodes/debug_ui.tscn
new file mode 100644
index 0000000..1cf603b
--- /dev/null
+++ b/half-earth/nodes/debug_ui.tscn
@@ -0,0 +1,22 @@
+[gd_scene load_steps=2 format=2]
+
+[ext_resource path="res://scripts/DebugUI.cs" type="Script" id=1]
+
+[node name="Debug UI" type="Control"]
+anchor_right = 1.0
+anchor_bottom = 1.0
+script = ExtResource( 1 )
+TicksLabelPath = NodePath("Ticks")
+
+[node name="Ticks" type="Label" parent="."]
+anchor_left = 1.0
+anchor_top = 1.0
+anchor_right = 1.0
+anchor_bottom = 1.0
+margin_right = -10.0
+margin_bottom = -10.0
+grow_horizontal = 0
+grow_vertical = 0
+text = "ticks: 0"
+align = 2
+valign = 2
diff --git a/half-earth/nodes/game.tscn b/half-earth/nodes/game.tscn
index c7bf9d9..1cf51a8 100644
--- a/half-earth/nodes/game.tscn
+++ b/half-earth/nodes/game.tscn
@@ -1,11 +1,19 @@
-[gd_scene load_steps=3 format=2]
+[gd_scene load_steps=5 format=2]
 
 [ext_resource path="res://nodes/grid.tscn" type="PackedScene" id=1]
 [ext_resource path="res://nodes/grid_cursor.tscn" type="PackedScene" id=2]
+[ext_resource path="res://nodes/debug_ui.tscn" type="PackedScene" id=3]
+[ext_resource path="res://nodes/clock.tscn" type="PackedScene" id=4]
 
-[node name="Root" type="Node2D"]
+[node name="Root" type="Node"]
 
 [node name="Grid" parent="." instance=ExtResource( 1 )]
 
 [node name="Cursor" parent="." instance=ExtResource( 2 )]
 Grid = NodePath("../Grid")
+
+[node name="Debug UI" parent="." instance=ExtResource( 3 )]
+
+[node name="Clock" parent="." instance=ExtResource( 4 )]
+
+[connection signal="OnTick" from="Clock" to="Debug UI" method="_on_Clock_OnTick"]
diff --git a/half-earth/scripts/Clock.cs b/half-earth/scripts/Clock.cs
new file mode 100644
index 0000000..9050073
--- /dev/null
+++ b/half-earth/scripts/Clock.cs
@@ -0,0 +1,31 @@
+using Godot;
+using System;
+
+public class Clock : Node
+{
+    [Signal]
+    delegate void OnTick(int ticks);
+    
+    private int _ticks = 0;
+
+    public override void _Input(InputEvent @event)
+    {
+        base._Input(@event);
+
+        if (@event is InputEventKey keyEvent && keyEvent.Pressed)
+        {
+            switch ((KeyList)keyEvent.Scancode)
+            {
+                case KeyList.Space:
+                    Tick();
+                    break;
+            }
+        }
+    }
+    
+    private void Tick()
+    {
+        _ticks++;
+        EmitSignal(nameof(OnTick), _ticks);
+    }
+}
diff --git a/half-earth/scripts/DebugUI.cs b/half-earth/scripts/DebugUI.cs
new file mode 100644
index 0000000..f8a8bdb
--- /dev/null
+++ b/half-earth/scripts/DebugUI.cs
@@ -0,0 +1,22 @@
+using Godot;
+using System;
+
+public class DebugUI : Control
+{
+    [Export]
+    public NodePath TicksLabelPath { private get; set; }
+    private Label _ticksLabel;
+    
+    public override void _Ready()
+    {
+        _ticksLabel = GetNode<Label>(TicksLabelPath);
+        SetTicksText(0);
+    }
+    
+    public void _on_Clock_OnTick(int ticks) => SetTicksText(ticks);
+    
+    private void SetTicksText(int ticks)
+    {
+        _ticksLabel.Text = $"ticks: {ticks}";
+    }
+}