diff --git a/week09/improvement/boids.py b/week09/improvement/boids.py
new file mode 100644
index 0000000..e1cba89
--- /dev/null
+++ b/week09/improvement/boids.py
@@ -0,0 +1,44 @@
+"""
+A deliberately bad implementation of 
+[Boids](http://dl.acm.org/citation.cfm?doid=37401.37406)
+for use as an exercise on refactoring.
+
+This code simulates the swarming behaviour of bird-like objects ("boids").
+"""
+
+from matplotlib import pyplot as plt
+from matplotlib import animation
+
+import random
+
+boids_x=[random.uniform(-450,50.0) for x in range(50)]
+boids_y=[random.uniform(300.0,600.0) for x in range(50)]
+boid_x_velocities=[random.uniform(0,10.0) for x in range(50)]
+boid_y_velocities=[random.uniform(-20.0,20.0) for x in range(50)]
+boids=(boids_x,boids_y,boid_x_velocities,boid_y_velocities)
+
+def update_boids(boids):
+    xs,ys,xvs,yvs=boids
+    # Fly towards the middle
+    for i in range(len(xs)):
+        for j in range(len(xs)):
+            xvs[i]=xvs[i]+(xs[j]-xs[i])*0.01/len(xs)
+    for i in range(len(xs)):
+        for j in range(len(xs)):
+            yvs[i]=yvs[i]+(ys[j]-ys[i])*0.01/len(xs)
+    # Fly away from nearby boids
+    for i in range(len(xs)):
+        for j in range(len(xs)):
+            if (xs[j]-xs[i])**2 + (ys[j]-ys[i])**2 < 100:
+                xvs[i]=xvs[i]+(xs[i]-xs[j])
+                yvs[i]=yvs[i]+(ys[i]-ys[j])
+    # Try to match speed with nearby boids
+    for i in range(len(xs)):
+        for j in range(len(xs)):
+            if (xs[j]-xs[i])**2 + (ys[j]-ys[i])**2 < 10000:
+                xvs[i]=xvs[i]+(xvs[j]-xvs[i])*0.125/len(xs)
+                yvs[i]=yvs[i]+(yvs[j]-yvs[i])*0.125/len(xs)
+    # Move according to velocities
+    for i in range(len(xs)):
+        xs[i]=xs[i]+xvs[i]
+        ys[i]=ys[i]+yvs[i]
\ No newline at end of file
diff --git a/week09/improvement/clustering.py b/week09/improvement/clustering.py
new file mode 100644
index 0000000..d6359ea
--- /dev/null
+++ b/week09/improvement/clustering.py
@@ -0,0 +1,32 @@
+"""This code implements the k-means clustering algorithm for 2 dimensions."""
+
+from math import *
+from random import *
+
+k=3
+
+lines = open('samples.csv', 'r').readlines()
+ps=[]
+for line in lines: ps.append(tuple(map(float, line.strip().split(','))))
+
+m=[ps[randrange(len(ps))], ps[randrange(len(ps))], ps[randrange(len(ps))]]
+
+alloc=[None]*len(ps)
+n=0
+while n<10:
+  for i in range(len(ps)):
+    p=ps[i]
+    d=[None] * 3
+    d[0]=sqrt((p[0]-m[0][0])**2 + (p[1]-m[0][1])**2)
+    d[1]=sqrt((p[0]-m[1][0])**2 + (p[1]-m[1][1])**2)
+    d[2]=sqrt((p[0]-m[2][0])**2 + (p[1]-m[2][1])**2)
+    alloc[i]=d.index(min(d))
+  for i in range(3):
+    alloc_ps=[p for j, p in enumerate(ps) if alloc[j] == i]
+    new_mean=(sum([a[0] for a in alloc_ps]) / len(alloc_ps), sum([a[1] for a in alloc_ps]) / len(alloc_ps))
+    m[i]=new_mean
+  n=n+1
+
+for i in range(3):
+  alloc_ps=[p for j, p in enumerate(ps) if alloc[j] == i]
+  print("Cluster " + str(i) + " is centred at " + str(m[i]) + " and has " + str(len(alloc_ps)) + " points.")
\ No newline at end of file
diff --git a/week09/improvement/trees.py b/week09/improvement/trees.py
new file mode 100644
index 0000000..dfa03f3
--- /dev/null
+++ b/week09/improvement/trees.py
@@ -0,0 +1,17 @@
+"""This code produces a tree-like plot."""
+
+from math import sin, cos
+from matplotlib import pyplot as plt
+s=1
+d=[[0,1,0]]
+plt.plot([0,0],[0,1])
+for i in range(5):
+    n=[]
+    for j in range(len(d)):
+        n.append([d[j][0]+s*sin(d[j][2]-0.1), d[j][1]+s*cos(d[j][2]-0.1), d[j][2]-0.1])
+        n.append([d[j][0]+s*sin(d[j][2]+0.1), d[j][1]+s*cos(d[j][2]+0.1), d[j][2]+0.1])
+        plt.plot([d[j][0], n[-2][0]],[d[j][1], n[-2][1]])
+        plt.plot([d[j][0], n[-1][0]],[d[j][1], n[-1][1]])
+    d=n
+    s*=0.6
+plt.savefig('tree.png')
\ No newline at end of file
diff --git a/week09/refactoring/initial_global.py b/week09/refactoring/initial_global.py
new file mode 100644
index 0000000..21f1323
--- /dev/null
+++ b/week09/refactoring/initial_global.py
@@ -0,0 +1,61 @@
+def average_age():
+    """Compute the average age of the group's members."""
+    all_ages = [person["age"] for person in group.values()]
+    return sum(all_ages) / len(group)
+
+
+def forget(person1, person2):
+    """Remove the connection between two people."""
+    group[person1]["relations"].pop(person2, None)
+    group[person2]["relations"].pop(person1, None)
+
+
+def add_person(name, age, job, relations):
+    """Add a new person with the given characteristics to the group."""
+    new_person = {
+        "age": age,
+        "job": job,
+        "relations": relations
+    }
+    group[name] = new_person
+
+
+group = {
+    "Jill": {
+        "age": 26,
+        "job": "biologist",
+        "relations": {
+            "Zalika": "friend",
+            "John": "partner"
+        }
+    },
+    "Zalika": {
+        "age": 28,
+        "job": "artist",
+        "relations": {
+            "Jill": "friend",
+        }
+    },
+    "John": {
+        "age": 27,
+        "job": "writer",
+        "relations": {
+            "Jill": "partner"
+        }
+    }
+}
+
+nash_relations = {
+    "John": "cousin",
+    "Zalika": "landlord"
+}
+
+add_person("Nash", 34, "chef", nash_relations)
+
+forget("Nash", "John")
+
+if __name__ == "__main__":
+    assert len(group) == 4, "Group should have 4 members"
+    assert average_age() == 28.75, "Average age of the group is incorrect!"
+    assert len(group["Nash"]["relations"]) == 1, "Nash should only have one relation"
+    print("All assertions have passed!")
diff --git a/week09/refactoring/initial_person_class.py b/week09/refactoring/initial_person_class.py
new file mode 100644
index 0000000..569d26d
--- /dev/null
+++ b/week09/refactoring/initial_person_class.py
@@ -0,0 +1,44 @@
+class Person:
+    """A class to represent an individual and their connections."""
+
+    def __init__(self, name, age, job):
+        """Create a new Person with the given name, age and job and no connections."""
+        self.name = name
+        self.age = age
+        self.job = job
+        self.connections = dict()
+
+    def add_connection(self, person, relation):
+        """Add a new connection to a person"""
+        if person in self.connections:
+            raise ValueError(f"I already know about {person.name}")
+        self.connections[person] = relation
+
+    def forget(self, person):
+        """Removes any connections to a person"""
+        pass
+
+
+def average_age(group):
+    """Compute the average age of the group's members."""
+    all_ages = [person.age for person in group]
+    return sum(all_ages) / len(group)
+
+
+if __name__ == "__main__":
+    # ...then create the group members one by one...
+    jill = Person("Jill", 26, "biologist")
+
+    # ...then add the connections one by one...
+    # Note: this will fail from here if the person objects aren't created
+    jill.add_connection(zalika, "friend")
+
+    # ... then forget Nash and John's connection
+    nash.forget(john)
+    # Then create the group
+    my_group = {jill, zalika, john, nash}
+
+    assert len(my_group) == 4, "Group should have 4 members"
+    assert average_age(my_group) == 28.75, "Average age of the group is incorrect!"
+    assert len(nash.connections) == 1, "Nash should only have one relation "
+    print("All assertions have passed!")
diff --git a/week09/refactoring/initial_two_classes.py b/week09/refactoring/initial_two_classes.py
new file mode 100644
index 0000000..a54d1b3
--- /dev/null
+++ b/week09/refactoring/initial_two_classes.py
@@ -0,0 +1,66 @@
+class Person:
+    """A class to represent an individual."""
+
+    def __init__(self, name, age, job):
+        """Create a new Person with the given name, age and job."""
+        self.name = name
+        self.age = age
+        self.job = job
+
+
+class Group:
+    """A class that represents a group of individuals and their connections."""
+
+    def __init__(self):
+        """Create an empty group."""
+        self.members = []
+        self.connections = {}
+
+    def size(self):
+        """Return how many people are in the group."""
+        pass
+
+    def contains(self, name):
+        """Check whether the group contains a person with the given name.
+        Useful to throw errors if we try to add a person who already exists or forget someone.
+        """
+        return any(member.name == name for member in self.members)
+
+    def add_person(self, name, age, job):
+        """Add a new person with the given characteristics to the group."""
+        self.members.append(Person(name, age, job))
+
+    def number_of_connections(self, name):
+        """Find the number of connections that a person in the group has"""
+        pass
+
+    def connect(self, name1, name2, relation, reciprocal=True):
+        """Connect two given people in a particular way.
+        Optional reciprocal: If true, will add the relationship from name2 to name 1 as well
+        """
+        pass
+
+    def forget(self, name1, name2):
+        """Remove the connection between two people."""
+        pass
+
+    def average_age(self):
+        """Compute the average age of the group's members."""
+        all_ages = [person.age for person in self.members]
+        return sum(all_ages) / self.size()
+
+
+if __name__ == "__main__":
+    # Start with an empty group...
+    my_group = Group()
+    # ...then add the group members one by one...
+    my_group.add_person("Jill", 26, "biologist")
+    # ...then their connections
+    my_group.connect("Jill", "Zalika", "friend")
+    # ... then forget Nash and John's connection
+    my_group.forget("Nash", "John")
+
+    assert my_group.size() == 4, "Group should have 4 members"
+    assert my_group.average_age() == 28.75, "Average age of the group is incorrect!"
+    assert my_group.number_of_connections("Nash") == 1, "Nash should only have one relation"
+    print("All assertions have passed!")
diff --git a/week09/versions/version1.py b/week09/versions/version1.py
new file mode 100644
index 0000000..73d0b03
--- /dev/null
+++ b/week09/versions/version1.py
@@ -0,0 +1,11 @@
+from visualisation import *
+from processing import *
+
+fs = ['81500.tab', '48151.tab', '62342.tab']
+R=[]
+R.append(analyse(preprocess(load(fs[0]),0.3)))
+R.append(analyse(preprocess(load(fs[1]),0.3)))
+R.append(analyse(preprocess(load(fs[2]),0.3)))
+
+for i in range(3):
+    save_figure(fu_map(R[i]))
diff --git a/week09/versions/version2.py b/week09/versions/version2.py
new file mode 100644
index 0000000..c1fa39a
--- /dev/null
+++ b/week09/versions/version2.py
@@ -0,0 +1,30 @@
+'''Analysis script for some DSEA measurements.'''
+
+import os
+
+from processing import analyse, is_valid, load, preprocess
+from visualisation import fu_map, save_figure
+
+
+def extract_mean(data_file):
+    """Load a dataset, smooth it and run the analysis algorithm on it.
+
+    :param data_file: input file containing raw data from an experiment.
+    """
+    assert os.path.exists(data_file), f"File not found: {data_file}"
+    assert is_valid(data_file), f"File {data_file} not in DSEA format."
+    data = load(data_file)
+    # This smoothing is necessary to avoid singular behaviour, see Kim (2012)
+    scaling = 0.3  # scaling factor to apply, from Reyes & Pace (2004)
+    smoothed_data = preprocess(data, scaling)
+    return analyse(smoothed_data)
+
+
+if __name__ == "__main__":
+    # The files from my last 3 experiments.
+    # Note that we can't run this on the data from the MT-3 because the
+    # files lack the header!
+    raw_files = ['81500.tab', '48151.tab', '62342.tab']
+    results = [extract_mean(input_file) for input_file in raw_files]
+    for result in results:
+        save_figure(fu_map(result))