lattices.py

# well'd do nested arrays, N rows inside an N-sized column (or vice versa)
# Then you can refer to a single spin with lattice[x][y]

# One approach, most obvious

N = 10

lattice = []
for x in range(N):
  lattice.append([])
  for y in range(N):
      lattice.append('DOWN')

# But we have some tricks up our sleeve, such as the list multiplication
N = 10
lattice = []
for x in range(N):
  lattice.append(['DOWN'] * N)

# And the list comprehensions which are just for loops for making lists
N = 10
lattice = [['DOWN'] * N for _ in range(N)]

# We can't do this!
N = 10
lattice = [['DOWN'] * N] * N
# because it would in fact create just one row and multiply that object
# and modifying one row would modify all of them...