Build a checkerboard
05AB1E, 26 bytes

2ÝD5+«v4Fy',N·yÉ+„bry3‹èJ,


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Explanation

2Ý                           # push [0,1,2]
  D5+                        # duplicate and add 5: [5,6,7]
     «                       # concatenate
      v                      # for each y in [0,1,2,5,6,7] do:
       4F                    # for each N in [0 ... 3] do:
         y                   # push y
          ',                 # push ","
            N·yÉ+            # push N*2+isOdd(y)
                 „br         # push "br"
                    y3‹è     # index into the string with y&lt;3
                        J,   # join everything to a string and print