What should I paint in this wall? Is the “door” for the bitcoin cafe
https://blossom.primal.net/3d3a44c61ca2c4476a4d273fe4edc55a07c411fc1493599ae6d6714e8357e10a.jpg
If you want a challenge, 
HEX of the Genesis block, or some stylized version of it
HEX of the Genesis block, or some stylized version of it1