Address PR comments

Author: stefpiatek

ch05construction/09patterns.ipynb

@@ -45,17 +45,18 @@
     "- If we find a bug in the functionality, this can be fixed in one place\n",
     "    - This is good because one change can be cascaded\n",
     "    - This can be bad because every subclass relies on its parent and changing one may need us to change the other\n",
-    "      (known tight coupling)\n",
+    "      (known as tight coupling)\n",
     "\n",
     "\n",
     "**Composition** *(has-a)*:\n",
     "\n",
     "- Create separate classes (component) which carry out the shared functionality.\n",
     "- Instead of inheriting a method, instantiate the class with the components as class variables,\n",
     "  when that functionality is required then we call that method on from the component.\n",
-    "- Unlike inheritance, you can design each component's interface so that it knows how to interact with other parts of your code\n",
+    "- Unlike inheritance, you can design each component's interface independently\n",
+    "  so that it knows how to interact with other parts of your code\n",
     "- Potential to have some code duplication\n",
-    "    - Doesn't have the problem of side effects cascading when you change alter one component.\n",
+    "    - Doesn't have the problem of side effects cascading when you alter one component.\n",
     "\n",
     "We've linked to an article which carries out a deep dive on this topic in the [other resources section](#Other-resources)"
    ]
@@ -420,6 +421,8 @@
     "        self.end = self.data[-1, 0]\n",
     "        self.range = self.end - self.start\n",
     "        self.step = self.range / self.count\n",
+    "        # create separate arrays as some algorithms require an array as an argument\n",
+    "        # and will throw an exception a view of an array is passed as an argument\n",
     "        self.times = self.data[:, 0].copy()\n",
     "        self.values = self.data[:, 1].copy()\n",
     "        self.plot_data = [self.times, self.values]\n",