def contiguous_cliques(x, step=1):
    """Partition *x* into contiguous cliques, where elements in clique differ by *step*."""
    if len(x) == 0:
        return []
    cliques, current, prev = [], [x[0]], x[0]
    for n in x[1:]:
        if n == prev + step:
            current.append(n)
        else:
            cliques.append(current)
            current = [n]
        prev = n
    cliques.append(current)
    return cliques