def chunks(input, size):
    return zip(*([iter(input)] * size))

print([' '.join(i + ' (s)' for i in c) for c in chunks('abcdefgh', 4)])
print([' (s) '.join(c) + ' (s)' for c in chunks('abcdefgh', 4)])

def interleave(lst, item):
    result = [None, item] * len(lst)
    result[0::2] = lst
    return result
	
print([' '.join(interleave(c, '(s)')) for c in chunks('abcdefgh', 4)])