diff --git a/app/tutorials/Tutorial 1 - Function Approximation.ipynb b/app/tutorials/Tutorial 1 - Function Approximation.ipynb
index 7395570933fd1ef6c2589d2a0d2cca7fece3e2aa..41a434f56095fb0df7d30de5543c2718be2492f1 100644
--- a/app/tutorials/Tutorial 1 - Function Approximation.ipynb	
+++ b/app/tutorials/Tutorial 1 - Function Approximation.ipynb	
@@ -16,10 +16,9 @@
    "outputs": [],
    "source": [
     "import sys\n",
-    "import os\n",
-    "import matplotlib.pyplot as plt\n",
     "import numpy as np\n",
     "import pythia as pt  # see doc: www.pythia-uq.com\n",
+    "import matplotlib.pyplot as plt\n",
     "\n",
     "sys.path.append(\"../../src\")\n",
     "from utils import Batman  # local imports"
diff --git a/app/tutorials/Tutorial 2 - Sensitivity Analysis.ipynb b/app/tutorials/Tutorial 2 - Sensitivity Analysis.ipynb
index 0bc5b841d12505330adac62cc38a3c03681ee9f0..caf26096bf57009020c48bb72df6b25d91e8cc3e 100644
--- a/app/tutorials/Tutorial 2 - Sensitivity Analysis.ipynb	
+++ b/app/tutorials/Tutorial 2 - Sensitivity Analysis.ipynb	
@@ -15,9 +15,12 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "import sys\n",
     "import numpy as np\n",
     "import pythia as pt  # see doc: www.pythia-uq.com\n",
-    "from utils import Sobol"
+    "\n",
+    "sys.path.append(\"../../src\")\n",
+    "from utils import Sobol  # local imports"
    ]
   },
   {
@@ -42,7 +45,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "sobol = Sobol(np.array([1, 2, 3, 4]))\n",
+    "a = np.array([1, 2, 3, 4])\n",
+    "sobol = Sobol(a)\n",
     "def target_function(y):\n",
     "    return sobol.eval(y)"
    ]
diff --git a/app/tutorials/Tutorial 3 - MCMC.ipynb b/app/tutorials/Tutorial 3 - MCMC.ipynb
index f2c7a200c6852f430ed03ae6f72cde64aed13e3a..8e232907aa7e298cdaded065f9e77abff47665ab 100644
--- a/app/tutorials/Tutorial 3 - MCMC.ipynb	
+++ b/app/tutorials/Tutorial 3 - MCMC.ipynb	
@@ -15,12 +15,15 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "import sys\n",
     "import numpy as np\n",
-    "import matplotlib.pyplot as plt\n",
-    "import matplotlib.cm as cmap\n",
     "import pythia as pt  # see doc: www.pythia-uq.com\n",
     "import emcee\n",
-    "from utils import Sine, Gaussian"
+    "import matplotlib.pyplot as plt\n",
+    "import matplotlib.cm as cmap\n",
+    "\n",
+    "sys.path.append(\"../../src\")\n",
+    "from utils import Sine, Gaussian  # local imports"
    ]
   },
   {
@@ -60,7 +63,7 @@
     "val = target_function(y)\n",
     "fig, ax = plt.subplot_mosaic([[\"sine\"]], constrained_layout=True, figsize=(10, 5))\n",
     "for j, valj in enumerate(val):\n",
-    "    ax[\"sine\"].plot(sine.points, valj, color=cmap.Greys((j+1)*20), label=f\"sample {j+1}\")\n",
+    "    ax[\"sine\"].plot(sine.points, valj, color=cmap.tab20(j), label=f\"sample {j+1}\")\n",
     "    ax[\"sine\"].legend()\n",
     "plt.show();"
    ]
diff --git a/app/tutorials/Tutorial 4 - Sampling.ipynb b/app/tutorials/Tutorial 4 - Sampling.ipynb
index ff1f1d023fa5302c70735d5311d633408d6257ce..5214b5e9d830fa63c0a2a03536d608297c346d72 100644
--- a/app/tutorials/Tutorial 4 - Sampling.ipynb	
+++ b/app/tutorials/Tutorial 4 - Sampling.ipynb	
@@ -16,9 +16,9 @@
    "outputs": [],
    "source": [
     "import numpy as np\n",
+    "import pythia as pt  # check doc: www.pythia-uq.com\n",
     "import matplotlib.pyplot as plt\n",
-    "import matplotlib.cm as cmap\n",
-    "import pythia as pt  # check doc: www.pythia-uq.com"
+    "import matplotlib.cm as cmap"
    ]
   },
   {