Uploaded even earlier gdscript implementation.

Euler.tscn

@@ -0,0 +1,48 @@
+[gd_scene load_steps=3 format=3 uid="uid://cn5rxob16gaic"]
+
+[ext_resource type="Script" path="res://Euler.gd" id="1_pj7ep"]
+
+[sub_resource type="LabelSettings" id="LabelSettings_dpjfj"]
+font_size = 50
+outline_size = 10
+outline_color = Color(0, 0, 0, 1)
+
+[node name="Euler" type="Control"]
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_pj7ep")
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+layout_mode = 1
+anchors_preset = 8
+anchor_left = 0.5
+anchor_top = 0.5
+anchor_right = 0.5
+anchor_bottom = 0.5
+offset_left = -75.5
+offset_top = -71.0
+offset_right = 75.5
+offset_bottom = 71.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="Test" type="Button" parent="VBoxContainer"]
+layout_mode = 2
+text = "Test
+"
+
+[node name="Calculate" type="Button" parent="VBoxContainer"]
+layout_mode = 2
+text = "Calculate"
+
+[node name="Label" type="Label" parent="VBoxContainer"]
+layout_mode = 2
+text = "Result"
+label_settings = SubResource("LabelSettings_dpjfj")
+
+[connection signal="button_down" from="VBoxContainer/Test" to="." method="_on_test_button_down"]
+[connection signal="button_down" from="VBoxContainer/Calculate" to="." method="_on_calculate_button_down"]