def make_seqs(a, b):
    """ Makes mutliple sequences of length b, from 0 to a. The sequences are represented 
        as tuples with start and stop numbers. Note that the stop number of one sequence is
        the start number for the next one, meaning that the stop number is NOT included.
    """
    seqs = []
    x = 0
    while x < a:
        x2 = x + b
        if x2 > a:
            x2 = a
            
        seqs.append( (x, x2) )
        x = x2
    
    return seqs