m = 3
simple_list = [1, 2, 3, 4]
res = []
for i in simple_list:
res += [i for _ in range(m)]
print(res)
# [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4]
n = 4
some_list = [6, 7, 8, 9]
replica = []
for i in some_list:
replica.append([i for _ in range(n)])
print(replica)
# [[6, 6, 6, 6], [7, 7, 7, 7], [8, 8, 8, 8], [9, 9, 9, 9]]