Block POS is the name of the product, right? Do you really want make a logo for a product? Wouldn't it make more sense to make a logo for an company/entity? I would love to see you come up with an entity name with the word "Pay" or "Payments". Something like Smartcoin Payments. So that's the entity. Then you could have products like Smartcoin POS, Smartcoin Wallet, etc. Or something along those lines. Just throwing it out there.
Well, yes and no. I would like people to think of it more as a network, where when you see the BlockPOS logo, you know you will be able to spend your crypto there, whatever that may be. BitShares Munich has a logo, but I want to push our product out there above anything else.
Just fyi, I thought of the qr code thing too, but our wallets and such will be supporting nfc very soon, so I decided to stay away from incorporating the qr into the logo.
I thought maybe some blocks, or something that represents the word BlockPOS, or blockchain, or point of sale, something that a merchant or customer could both identify with. Take a look at these examples:
http://50north.de/wp-content/uploads/2011/01/payment-icons.jpg