A fun and inventive way of doing this particular challenge.
I like the incongruity of the background you chose - the velvety green-ness is a wonderful contrast to the harsh tacks.
I would like to see the tacks up a little closer though. I know they're tacks because of the challenge, but if you showed me this photo and I didn't know the challenge, I might be confused.
Okay, you got me on this one! Only problem is there are no tacks in this image. ;) Wonder where they are going? Is that where little tacks come from? Excellent stop capture - I know it couldn't have been easy! 8 from me!
Lol! Good idea and funny but the tacks are too small for this to work 100% IMHO. If you would have had this exact image with a couple of more tacks that were closer and therefore bigger it would really have hit the spot for me but I still like this very much, way better than most in the challenge so I gave it an 7, mostly because of your imagination.