design 21 has some potential... the manta shapes around the play symbol could be used to make an H and an O. Here is a link to some images of manta rays:
https://www.google.com/search?q=manta+ray&es_sm=91&tbm=isch&tbo=u&source=univ&sa=X&ei=CzUrVebNNYSrgwS8noCQDQ&ved=0CIIBEIke&biw=1440&bih=782&dpr=2 Maybe if we made them look more like mantas swimming in a H and O there could be something there... I like having something as a stand alone image that represents the letters. I would be willing to play with a different color scheme if you felt that would help. Thanks for the great work so far!