matrix = [[1,2],[3,4]]
new_copies = []
counter = 0

for i in range(0,2):
    for k in range(0,2):
        if matrix[i][k] > 3:
            exec("item%s = matrix[:]" % counter)
            exec("item%s[i][k] = matrix[i][k] + 10" % counter)
            exec("new_copies.append(item%s)" % counter)
            counter += 1

print(matrix)
print(new_copies)

new_matrix = original_matrix[:]