I have a dozen sequences to solve where I am given the first three and have to fill in the following five. In all the cases the sequence repeats so that numbers 5 - 8 are identical with numbers 1 - 4, so that there is really only one to work out - number four. There is just this one that has me stumped:

Its tempting to draw an eighth slice but then the next would surely have to be a one sixteenth slice and so on, and this can't be right since it would not repeat. Number five has to be the same as number one - empty. So what fits in number 4 that logically progresses to give an empty circle again? My intuition says a straight verticle line but I can't see the logic!

Help!

Thanks

Lea