I like #13 - the way the questions marks come together to form the 8 is great - I don't know if the site would look good with the black background. Is #12 the same without the background (it doesn't look quite the same)?
I am not sure the question marks are as obvious in #16 and #18 - but they look good.
i apologize before, i have withdrawn all my designs Sir.. it because someone has told me that i cant use this concept because someone has use it before me :) ( even it was totally different shape n i dont cony anyone ;) )
so, to respect previous designer, i have to withdraw it all Sir.. may u get your best designs here :)