{ /[b1][b_double] | b2  }
{ /[b1]/[1][b!]   | b3  }
{ /[b2][b_double] | b4  }
{ /[b2]/[1][b!]   | b5  }
{ /[b3][b_double] | b6  }
{ /[b3]/[1][b!]   | b7  }
{ /[b4][b_double] | b8  }
{ /[b4]/[1][b!]   | b9  }
{ /[b5][b_double] | bxA }
{ /[b5]/[1][b!]   | bxB }

{ /[b3][b_square] | ^1  }
{ /[^1][b_square] | ^2  }
{ /[^2][b_square] | ^3  }
{ /[^3][b_square] | ^4  }
{ /[^4][b_square] | ^5  }
{ /[^5][b_square] | ^6  }
{ /[^6][b_square] | ^7  }
{ /[^7][b_square] | ^8  }
{ /[^8][b_square] | ^9  }
{ /[^9][b_square] | ^A  }
{ /[^A][b_square] | ^B  }
{ /[^B][b_square] | ^C  }