Not sure if this is simpler or better, but here's a way to do it with a generator:
value = 100 count = 0 def valueGen(): global value global count while(value >= 0): if(value == 100): yield value value -= 1 else: if(count & 1): yield value else: yield value value -= 1 count = count + 1 series = [] gen = valueGen() for item in gen: print item series.append(item) print series -- http://mail.python.org/mailman/listinfo/python-list