anchor.diff:      ( 28,  0,  0,  0,  0,  0,  0,  0,  0,  0), // 16 btGrassSand3
       ( 29, 30,  0,  0,  0,  0,  0,  0,  0,  0), // 17 btSand
       (137,132,131,130,129, 18,128,136,135,134), // 18 btStone
  -    (308,147,146,145,144, 20,  0,  0,  0,  0), // 19 btGold
  +    (307,147,146,145,144, 20,  0,  0,  0,  0), // 19 btGold
       (156,157,158,159,201,  0,  0,  0,  0,  0), // 20 btEgold
       (260,151,150,149,148, 22,  0,  0,  0,  0), // 21 btIron
       (160,161,162,163,164,  0,  0,  0,  0,  0), // 22 btEIron
  
positive.code: 	  True,  True,  False, False, False,   True,  True,  False, False, False,   False, False, False, True,  True,    True,
      False, True,  False, False, False,   False, True,  True,  True,  False,   True,  False, False, False, True,    True,
      True,  False, True,  False, False,   False, True,  True,  True,  False,   True,  False, False, False, True,    True,
      False, True,  True,  False, False,   False, False, False, False, False,   False, False, False, False, False,   False
    );
  
  implementation
  
negative.code:     False  // 23 btDark
    );
  
    WT: array[0..399] of Boolean = ( // Walkable tiles
    //  0      1      2      3      4        5      6      7      8      9       10     11     12     13     14       15
      True,  True,  True,  True,  False,   True,  True,  False, True,  True,    False, True,  False, True,  True,    False,
      True,  True,  True,  True,  True,    True,  True,  False, False, True,    True,  True,  True,  True,  True,    True,
  