diff --git a/NOTES.md b/NOTES.md
index 988643c..1a8981b 100644
--- a/NOTES.md
+++ b/NOTES.md
@@ -66,6 +66,12 @@ Mám v plánu udělat texture masku pro tvarování protálů. S házením stín
 
 > Dal by se udělat celkem jednoduchý algoritmus co by generoval mesh "s prohlubní" pro jakýkoliv nákres zepředu. Obdélník je nejjednodušší, ale udělat oblouček by asi nebyl problém.
 >
-> **Custom Mesh subclassa?**
+> Podobně jak se dá "kreslit" s CSG polygonem. Ale to by byl teda komplikovaný editor widget. Ty oblouky bysme asi chtěli hladké - to vypadá na něco na styl Curve editoru... ugh
+>
+> ![csg-polygon](assets/csg-polygon.png)
+>
+> [Cyclops Level Editor](https://github.com/blackears/cyclopsLevelBuilder/blob/master/doc/index.md#display-mode)
+
+**Custom Mesh subclassa?**
 
 - Custom mesh subclassa je trochu divná věc. Když to všechno nastaví jeden editorový Node tak to bude asi lepší. Custom mesh se mi přegenerovává při každém spuštění, ale já chci aby se prostě "zapekl" a uložil a nazdar bazar...
diff --git a/assets/csg-polygon.png b/assets/csg-polygon.png
new file mode 100644
index 0000000..8872abd
Binary files /dev/null and b/assets/csg-polygon.png differ
diff --git a/levels/level_cube_portals.tscn b/levels/level_cube_portals.tscn
index c563475..af93866 100644
--- a/levels/level_cube_portals.tscn
+++ b/levels/level_cube_portals.tscn
@@ -162,7 +162,6 @@ portal = NodePath("../Portal A")
 
 [node name="Outer" type="CSGBox3D" parent="."]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 2.78925)
-visible = false
 size = Vector3(2.2, 3.2, 0.25)
 
 [node name="CSGCombiner3D" type="CSGCombiner3D" parent="Outer"]
diff --git a/levels/test_internal_nodes.gd b/levels/test_internal_nodes.gd
new file mode 100644
index 0000000..d82085b
--- /dev/null
+++ b/levels/test_internal_nodes.gd
@@ -0,0 +1,43 @@
+@tool
+extends Node3D
+
+
+
+func _add_inspector_buttons() -> Array:
+	var buttons: Array = []
+	
+	buttons.push_back({
+		"name": "Regular cube mesh",
+		"pressed": _add_regular_cube_mesh
+	})
+	buttons.push_back({
+		"name": "Internal cube mesh",
+		"pressed": _add_internal_cube_mesh
+	})
+	buttons.push_back({
+		"name": "Delete all children",
+		"pressed": func(): for child in get_children(true): child.queue_free()
+	})
+	
+	return buttons
+
+func _add_regular_cube_mesh() -> void:
+	var m = MeshInstance3D.new()
+	var b = BoxMesh.new()
+	m.mesh = b
+	add_child(m, true)
+	m.owner = self
+	m.position.x = 1.5 * get_child_count(true)
+
+func _add_internal_cube_mesh() -> void:
+	var m = MeshInstance3D.new()
+	var b = BoxMesh.new()
+	m.mesh = b
+	add_child(m, true, Node.INTERNAL_MODE_BACK)
+	
+	var mat = StandardMaterial3D.new()
+	mat.albedo_color = Color("ff4c4e")
+	b.material = mat
+	
+	m.owner = self
+	m.position.x = 1.5 * get_child_count(true)
diff --git a/levels/test_internal_nodes.gd.uid b/levels/test_internal_nodes.gd.uid
new file mode 100644
index 0000000..471748c
--- /dev/null
+++ b/levels/test_internal_nodes.gd.uid
@@ -0,0 +1 @@
+uid://ouk76qr5gpq0
diff --git a/levels/test_internal_nodes.tscn b/levels/test_internal_nodes.tscn
new file mode 100644
index 0000000..3a40a6f
--- /dev/null
+++ b/levels/test_internal_nodes.tscn
@@ -0,0 +1,38 @@
+[gd_scene load_steps=8 format=3 uid="uid://bnrph4k6wpruy"]
+
+[ext_resource type="Script" uid="uid://ouk76qr5gpq0" path="res://levels/test_internal_nodes.gd" id="1_glqbe"]
+
+[sub_resource type="BoxMesh" id="BoxMesh_glqbe"]
+
+[sub_resource type="BoxMesh" id="BoxMesh_dodl2"]
+
+[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_wgeau"]
+albedo_color = Color(1, 0.298039, 0.305882, 1)
+
+[sub_resource type="BoxMesh" id="BoxMesh_j0q2q"]
+material = SubResource("StandardMaterial3D_wgeau")
+
+[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_47wcs"]
+albedo_color = Color(1, 0.298039, 0.305882, 1)
+
+[sub_resource type="BoxMesh" id="BoxMesh_bkhqo"]
+material = SubResource("StandardMaterial3D_47wcs")
+
+[node name="test_internal_nodes" type="Node3D"]
+script = ExtResource("1_glqbe")
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 1.5, 0, 0)
+mesh = SubResource("BoxMesh_glqbe")
+
+[node name="MeshInstance3D3" type="MeshInstance3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 4.5, 0, 0)
+mesh = SubResource("BoxMesh_dodl2")
+
+[node name="MeshInstance3D2" type="MeshInstance3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3, 0, 0)
+mesh = SubResource("BoxMesh_j0q2q")
+
+[node name="MeshInstance3D4" type="MeshInstance3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 6, 0, 0)
+mesh = SubResource("BoxMesh_bkhqo")