thanks for your submissions so far 
You should add a deadline and of course original work.
yes, sorry about that... i have edited the op post.
please do submit original work only.
My opinion to give enough time, 2 weeks at least
- this will make more people know about that (good advertisement for Leaf)
- the reward will increase
- more professional designer will participate
- more value for our action to change the logo
- best results