I, X, X, X, I, X, I, I, I, I, I, I, I, I, I, _
As ever, please do NOT post your answers, but do feel free to say if you think you have solved it and how long it took. Solution on Monday.
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.