diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3ee18f4a..26be1350 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.11"]
+        python-version: ["3.12"]
 
     steps:
       - name: Install system packages
diff --git a/docs/usage_spherical_tokamak.rst b/docs/usage_spherical_tokamak.rst
index 6c2c67d9..90c68d2b 100644
--- a/docs/usage_spherical_tokamak.rst
+++ b/docs/usage_spherical_tokamak.rst
@@ -1,26 +1,3 @@
-Usage
-=====
-
-There are two main reactors to choose from, Tokamak and Spherical Tokamak.
-These can be built with:
-- A radial and vertical build
-- A radial build and plasma elongation.
-
-The former gives the user more control of the size of components allowing reactor blankets to vary both radially and vertically.
-The later allows reactors to be built with a minimal number of parameters.
-In all cases it is possible to add additional components such as divertors, poloidal and toroidal magnets and any self made geometry as a CadQuery Workplane.
-The reactors can be varied in terms of their radial build, vertical build, elongation and triangularity which gives a lot of variability.
-These examples show how to make various reactors with and without different components, each example is minimal and aims to show a single feature, you will have to combine examples to make a complete model. 
-
-
-
-.. toctree::
-   :maxdepth: 3
-
-   usage-tokamak
-   usage-spherical-tokamak
-
-
 
 Spherical tokamak from plasma
 -----------------------------
diff --git a/docs/usage_tokamak.rst b/docs/usage_tokamak.rst
index 391042cb..6e05aa9b 100644
--- a/docs/usage_tokamak.rst
+++ b/docs/usage_tokamak.rst
@@ -1,26 +1,3 @@
-Usage
-=====
-
-There are two main reactors to choose from, Tokamak and Spherical Tokamak.
-These can be built with:
-- A radial and vertical build
-- A radial build and plasma elongation.
-
-The former gives the user more control of the size of components allowing reactor blankets to vary both radially and vertically.
-The later allows reactors to be built with a minimal number of parameters.
-In all cases it is possible to add additional components such as divertors, poloidal and toroidal magnets and any self made geometry as a CadQuery Workplane.
-The reactors can be varied in terms of their radial build, vertical build, elongation and triangularity which gives a lot of variability.
-These examples show how to make various reactors with and without different components, each example is minimal and aims to show a single feature, you will have to combine examples to make a complete model. 
-
-
-
-.. toctree::
-   :maxdepth: 3
-
-   usage_tokamak
-   usage_spherical_tokamak
-
-
 
 Tokamak from plasma
 -------------------
diff --git a/examples/tokamak_from_plasma_with_divertor.py b/examples/tokamak_from_plasma_with_divertor.py
index bf7e0065..a6b83d93 100644
--- a/examples/tokamak_from_plasma_with_divertor.py
+++ b/examples/tokamak_from_plasma_with_divertor.py
@@ -12,21 +12,18 @@
 
 my_reactor = paramak.tokamak_from_plasma(
     radial_build=[
-        [
-            (paramak.LayerType.GAP, 10),
-            (paramak.LayerType.SOLID, 30),
-            (paramak.LayerType.SOLID, 50),
-            (paramak.LayerType.SOLID, 10),
-            (paramak.LayerType.SOLID, 120),
-            (paramak.LayerType.SOLID, 20),
-            (paramak.LayerType.GAP, 60),
-            (paramak.LayerType.PLASMA, 300),
-            (paramak.LayerType.GAP, 60),
-            (paramak.LayerType.SOLID, 20),
-            (paramak.LayerType.SOLID, 120),
-            (paramak.LayerType.SOLID, 10),
-        ],
-        # [(paramak.LayerType.GAP, 300), ("lower_divertor", 150)],
+        (paramak.LayerType.GAP, 10),
+        (paramak.LayerType.SOLID, 30),
+        (paramak.LayerType.SOLID, 50),
+        (paramak.LayerType.SOLID, 10),
+        (paramak.LayerType.SOLID, 120),
+        (paramak.LayerType.SOLID, 20),
+        (paramak.LayerType.GAP, 60),
+        (paramak.LayerType.PLASMA, 300),
+        (paramak.LayerType.GAP, 60),
+        (paramak.LayerType.SOLID, 20),
+        (paramak.LayerType.SOLID, 120),
+        (paramak.LayerType.SOLID, 10),
     ],
     elongation=2,
     triangularity=0.55,
diff --git a/pyproject.toml b/pyproject.toml
index b100d61b..57228ae4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -45,7 +45,8 @@ docs = [
     "numpy<=1.26.4",
     "mpmath",
     "sympy",
-    "scipy"
+    "scipy",
+    "ipython"
 ]
 
 [tool.black]
diff --git a/src/paramak/assemblies/spherical_tokamak.py b/src/paramak/assemblies/spherical_tokamak.py
index 9103b326..5b2ccd96 100644
--- a/src/paramak/assemblies/spherical_tokamak.py
+++ b/src/paramak/assemblies/spherical_tokamak.py
@@ -235,7 +235,7 @@ def spherical_tokamak(
     if len(extra_intersect_shapes)>0:
         all_shapes = []
         for shape in inner_radial_build + blanket_layers:
-            all_shapes.extend(shape)
+            all_shapes.append(shape)
 
         # makes a union of the the radial build to use as a base for the intersect shapes
         reactor_compound=inner_radial_build[0]
diff --git a/src/paramak/assemblies/tokamak.py b/src/paramak/assemblies/tokamak.py
index 0a778c43..505ef437 100644
--- a/src/paramak/assemblies/tokamak.py
+++ b/src/paramak/assemblies/tokamak.py
@@ -262,7 +262,7 @@ def tokamak(
     if len(extra_intersect_shapes)>0:
         all_shapes = []
         for shape in inner_radial_build + blanket_layers:
-            all_shapes.extend(shape)
+            all_shapes.append(shape)
 
         # makes a union of the the radial build to use as a base for the intersect shapes
         reactor_compound=inner_radial_build[0]