found yesturday, some clue where hidden by invisible UV paint ! that's why you had to be physically in front of it.
The one who found it promote by the way his company 
The words were encoded - I still don't figure how - and where french words for banker, wear, lie, people, fight, hope, union, citizen, drive, triumph, horizon, yellow.
It was a good idea, the painting is also reflecting the mood of the time in France, the Liberty Leading the People is not topless anymore.
For the next time, I'd like a more universal riddle.

not yet => https://www.blockchain.com/btc/address/1NqPwPp7hEXZ3Atj77Ue11xAEMmXqAXwrQ

but I wonder why you have to be physically in front of it to guess the whole key ?

facing eternity, mining in a medium or big pool would be exactly the same - even if you try solo mining.
but an human being so far isn't eternal and could be unlucky his life long :-)
except for the horrible one we shouldn't mention an x4 or a x5 block can occur frome time to time, the pool has just to gather enough hashing power to reduce interval without finding block for exemple once a month.
its on a good way, I've just seen 55Ph, can a mathematician draw something about it ?
And many thanks Doc for this pool !

for Canaan, Steve helped me for a order made in july, finaly received in september, it was for a single 741, just before they stop shipping small order.
For Minerwarez, the late november batch was only delayed a few days, and they provide a very good support for importation process.
It's easy to say, but don't behave like me in august, while I was thinking that I was the victim of a scam, keep in mind that in that period lot of people are on holidays, and I hope that the difficulties you face will disappear as soon as possible !

for the 20th november batch, I've received a mail telling me that there will be something like two weeks of delay.

Sylvain

It's me again, my avalon 741 has been received few weeks ago and is at work !

Just because of few grain of sand (bank mistake, name mismatch) everything went wrong for me.

Many thanks to steven and his team - Lily and Jasmine particulary - to have solved my issue.

Sylvain.

I've sent them money the 19th of july 2017, and .... nothing.
I've been opening tickets, they kindly answered but nothing.

So , more than two month later, I'm sure that canaan.io is not legits, and so must be minerwarez.com

Be carfull !

edit 19/09/2017 : I've got finaly an answer of Lily Han of canaan.io, a mistake of my bank about the fees of transfert, my name not figuring of the transfert and a lot of work cause this