# use https://pythontutor.com/visualize.html#mode=edit to visualize

a = 10
b = [1, 2, 3, 4, 5]
c = a
d = c

m = [[1, 1], [1, 1]]
print(m)
m[0][0] = 0
print(m)

m = [[1, 1]]*2
print(m)
m[0][0] = 0
print(m)


m = []
for i in range(2):
  m.append([1, 1])
print(m)

m[0][0] = 0
print(m)


m = []
row = []
for i in range(2):
  row.append(1)

m.append(row)
m.append(row)
print(m)
m[0][0] = 0
print(m)

x = [1, 2]
y = [3, 4]
z = x+y
print(z)
x[0] = 0
print(x)
print(z)

k = [1, 2]
l = [3, 4]
k.append(l)
print(k)
l[0] = 0
print(l)
print(k)

o = [[1], [2]]
p = [[3], [4]]
q = o + p
print(q)
o[0][0] = 0
print(o)
print(q)