anchor.diff:      ( 19, 20,255,255,255), // 20 btEgold
       ( 21, 22,255,255,255), // 21 btIron
       ( 21, 22,255,255,255), // 22 btEIron
  -    ( 21, 22,255,255,255)  // 23 btDark
  +    ( 22, 20,255,255,255)  // 23 btDark
     );
   
     // Choose minimal value (biome) by specific rules
  
positive.code:       // Note: conditions are for special transitions between iron and gold mountains
          // Left Top Right %0111
          7: begin
            if (B[Y1,X1,1,1] <= Byte(btStone)) then
              begin LT := B[Y1,X1,1,1]; RT := B[Y1,X1,1,1]; RD := B[Y1,X1,2,1]; LD := B[Y1,X1,2,1]; end else
              begin LT := B[Y1,X1,1,1]; RT := B[Y1,X1,1,1]; RD := B[Y1,X1,2,2]; LD := B[Y1,X1,2,0]; end;
          end;
          // Left Down Right %1101
         13: begin
           if (B[Y1,X1,1,1] <= Byte(btStone)) then
             begin LT := B[Y1,X1,0,1]; RT := B[Y1,X1,0,1]; RD := B[Y1,X1,1,1]; LD := B[Y1,X1,1,1]; end else
             begin LT := B[Y1,X1,0,0]; RT := B[Y1,X1,0,2]; RD := B[Y1,X1,1,1]; LD := B[Y1,X1,1,1]; end;
         end;
          // Top Right Down %1110
         14: begin
           if (B[Y1,X1,1,1] <= Byte(btStone)) then
             begin LT := B[Y1,X1,1,0]; RT := B[Y1,X1,1,1]; RD := B[Y1,X1,1,1]; LD := B[Y1,X1,1,0]; end else
             begin LT := B[Y1,X1,0,0]; RT := B[Y1,X1,1,1]; RD := B[Y1,X1,1,1]; LD := B[Y1,X1,2,0]; end;
         end;
          // Top Left Down %1011
         11: begin
           if (B[Y1,X1,1,1] <= Byte(btStone)) then
             begin LT := B[Y1,X1,1,1]; RT := B[Y1,X1,1,2]; RD := B[Y1,X1,1,2]; LD := B[Y1,X1,1,1]; end else
             begin LT := B[Y1,X1,1,1]; RT := B[Y1,X1,0,2]; RD := B[Y1,X1,2,2]; LD := B[Y1,X1,1,1]; end;
          end;
  
negative.code:     ( 0, 0, 0, 0, 4,  7, 7, 7, 0, 9, 10,-1,-1,13,15, 15,15,15, 0,-1, -1,-1,-1,-1), // 20 btEgold
      ( 0, 0, 0, 0, 4,  7, 7, 7, 0, 9, 10,-1,-1,13,15, 15,15,15, 0,20, 20,-1,-1,-1), // 21 btIron
      ( 0, 0, 0, 0, 4,  7, 7, 7, 0, 9, 10,-1,-1,13,15, 15,15,15, 0,20, 20,-1,-1,-1), // 22 btEIron
      (-1,-1,-1,-1,-1, -1,-1,-1,-1,-1, -1,-1,-1,-1,-1, -1,-1,-1,-1,20, 20,22,22,-1)  // 23 btDark
    );
  
    T_FIX: array[0..len_BIOME-1,0..len_BIOME-1] of Byte = ( // Transition fixer
  