gistfile1.py

def raskolbas(iterable, r):
    """
    >>> raskolbas(['one', 'two', 'three', 'four', 'five'], 2)
    [['one', 'two'], ['two', 'three'], ['three', 'four'], ['four', 'five']]
    """
    l = list(iterable)
    return reduce(lambda x, y: (x.append(x[-1][-r+1:] + [y]), x)[-1], l[r:], [l[:r]])


def zakolbas(iterable):
    """
    >>> zakolbas([['one', 'two'], ['two', 'three'], ['three', 'four'], ['four', 'five']])
    ['one', 'two', 'three', 'four', 'five']
    """
    return reduce(lambda x, y: (x.append(y[-1]), x)[-1], iterable[1:], iterable[0])

if __name__ == '__main__':
    import doctest
    doctest.testmod()
    print "Ok."