diff --git a/.DS_Store b/.DS_Store
index 731816a..f88ce6d 100644
Binary files a/.DS_Store and b/.DS_Store differ
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..63d12aa
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+diffusion.so
diff --git a/5_f2py/Makefile b/5_f2py/Makefile
new file mode 100644
index 0000000..3468e69
--- /dev/null
+++ b/5_f2py/Makefile
@@ -0,0 +1,2 @@
+diffusion.so: diffusion.f90
+	f2py -c -m diffusion --fcompiler=gfortran --opt='-O3' diffusion.f90
diff --git a/5_f2py/diffusion.f90 b/5_f2py/diffusion.f90
new file mode 100644
index 0000000..6cb5821
--- /dev/null
+++ b/5_f2py/diffusion.f90
@@ -0,0 +1,17 @@
+SUBROUTINE evolve(grid, scratch, D, dt, N, M)
+    !f2py threadsafe
+    !f2py intent(in) grid
+    !f2py intent(inplace) scratch
+    !f2py intent(in) D
+    !f2py intent(in) dt
+    !f2py intent(hide) N
+    !f2py intent(hide) M
+    INTEGER :: N, M
+    DOUBLE PRECISION, DIMENSION(N,M) :: grid, scratch
+    DOUBLE PRECISION, DIMENSION(N-2, M-2) :: laplacian
+    DOUBLE PRECISION :: D, dt
+
+    laplacian = grid(3:N, 2:M-1) + grid(1:N-2, 2:M-1) + &
+                grid(2:N-1, 3:M) + grid(2:N-1, 1:M-2) - 4 * grid(2:N-1, 2:M-1)
+    scratch(2:N-1, 2:M-1) = grid(2:N-1, 2:M-1) + D * dt * laplacian
+END SUBROUTINE evolve
diff --git a/5_f2py/diffusion_fortran.py b/5_f2py/diffusion_fortran.py
new file mode 100644
index 0000000..06b1ce1
--- /dev/null
+++ b/5_f2py/diffusion_fortran.py
@@ -0,0 +1,24 @@
+from diffusion import evolve
+import numpy as np
+import time
+
+grid_shape = (512, 512)
+
+
+def run_experiment(num_iterations):
+    scratch = np.zeros(grid_shape, dtype=np.double, order='F')
+    grid = np.zeros(grid_shape, dtype=np.double, order='F')
+
+    block_low = int(grid_shape[0] * .4)
+    block_high = int(grid_shape[0] * .5)
+    grid[block_low:block_high, block_low:block_high] = 0.005
+
+    start = time.time()
+    for i in range(num_iterations):
+        evolve(grid, scratch, 1.0, 0.1)
+        grid, scratch = scratch, grid
+    return time.time() - start
+
+if __name__ == "__main__":
+    t = run_experiment(500)
+    print t
diff --git a/codes/fib.py b/codes/fib.py
new file mode 100644
index 0000000..efaa582
--- /dev/null
+++ b/codes/fib.py
@@ -0,0 +1,8 @@
+def fib(n):
+    """Print the Fibonacci series up to n."""
+    a, b = 0, 1
+    while b < n:
+        print (b)
+        a, b = b, a + b
+
+print (fib(2000))
diff --git a/f2py/Makefile b/f2py/Makefile
new file mode 100644
index 0000000..6da5d16
--- /dev/null
+++ b/f2py/Makefile
@@ -0,0 +1,4 @@
+diffusion.so: diffusion.c
+	gcc -O3 -std=gnu99 -c diffusion.c
+	gcc -shared -o diffusion.so diffusion.o
+	rm -rf diffusion.o
diff --git a/f2py/diffusion.f90 b/f2py/diffusion.f90
new file mode 100644
index 0000000..6cb5821
--- /dev/null
+++ b/f2py/diffusion.f90
@@ -0,0 +1,17 @@
+SUBROUTINE evolve(grid, scratch, D, dt, N, M)
+    !f2py threadsafe
+    !f2py intent(in) grid
+    !f2py intent(inplace) scratch
+    !f2py intent(in) D
+    !f2py intent(in) dt
+    !f2py intent(hide) N
+    !f2py intent(hide) M
+    INTEGER :: N, M
+    DOUBLE PRECISION, DIMENSION(N,M) :: grid, scratch
+    DOUBLE PRECISION, DIMENSION(N-2, M-2) :: laplacian
+    DOUBLE PRECISION :: D, dt
+
+    laplacian = grid(3:N, 2:M-1) + grid(1:N-2, 2:M-1) + &
+                grid(2:N-1, 3:M) + grid(2:N-1, 1:M-2) - 4 * grid(2:N-1, 2:M-1)
+    scratch(2:N-1, 2:M-1) = grid(2:N-1, 2:M-1) + D * dt * laplacian
+END SUBROUTINE evolve
diff --git a/f2py/diffusion_fortran.py b/f2py/diffusion_fortran.py
new file mode 100644
index 0000000..06b1ce1
--- /dev/null
+++ b/f2py/diffusion_fortran.py
@@ -0,0 +1,24 @@
+from diffusion import evolve
+import numpy as np
+import time
+
+grid_shape = (512, 512)
+
+
+def run_experiment(num_iterations):
+    scratch = np.zeros(grid_shape, dtype=np.double, order='F')
+    grid = np.zeros(grid_shape, dtype=np.double, order='F')
+
+    block_low = int(grid_shape[0] * .4)
+    block_high = int(grid_shape[0] * .5)
+    grid[block_low:block_high, block_low:block_high] = 0.005
+
+    start = time.time()
+    for i in range(num_iterations):
+        evolve(grid, scratch, 1.0, 0.1)
+        grid, scratch = scratch, grid
+    return time.time() - start
+
+if __name__ == "__main__":
+    t = run_experiment(500)
+    print t