anchor.diff:    String testJson4 = '{"_levelNum":1,"_levelTimeSec":120,"_requiredScore":1000,"_comboHoldTime":8,"_colors":[ "normalBlock" ],"_blocks":[ "red","blue","green","yellow" ],"_startField":[                                     [ { "_color":"red", "x": 0, "y": 1 },  { "_color":"red", "x": 1, "y": 1 },  { "_color":"red", "x": 2, "y": 1 } ],    [ { "_color":"red", "x": 1, "y": 2 } ],    [ { "_color":"red", "x": 1, "y": 3 } ]   ]}';
     String gravityTest = '{"_levelNum":1,"_levelTimeSec":120,"_requiredScore":1000,"_comboHoldTime":8,"_colors":[ "normalBlock" ],"_blocks":[ "red","blue","green","yellow" ],"_startField":[ [ { "_color":"red", "x": 3, "y": 5 }   ]]}';
     String gravityTestFusion = '{"_levelNum":1,"_levelTimeSec":120,"_requiredScore":1000,"_comboHoldTime":8,"_colors":[ "normalBlock" ],"_blocks":[ "red","blue","green","yellow" ],"_startField":[                                     [ { "_color":"red", "x": 2, "y": 8 }, { "_color":"red", "x": 3, "y": 8 }, { "_color":"red", "x": 4, "y": 8 }, { "_color":"red", "x": 5, "y": 8 }, { "_color":"red", "x": 6, "y": 8 }],                                   [ { "_color":"red", "x": 3, "y": 7 }, { "_color":"red", "x": 4, "y": 7 }, { "_color":"red", "x": 5, "y": 7 } ]                                   ]}';
  -  String firstViewTest = '{"_levelNum":1,"_levelTimeSec":120,"_requiredScore":30,"_comboHoldTime":2,"_blocks":[ "normalBlock" ],"_colors":[ "red","blue","green","yellow","orange" ],"_startField":[  [  { "_color":"red", "x": 0, "y": 1 },  { "_color":"red", "x": 1, "y": 1 },  { "_color":"blue", "x": 2, "y": 1 },  { "_color":"yellow", "x": 3, "y": 1 },  { "_color":"red", "x": 4, "y": 1 },  { "_color":"red", "x": 5, "y": 1 },  { "_color":"yellow", "x": 6, "y": 1 },  { "_color":"blue", "x": 7, "y": 1 }  ],    [  { "_color":"blue", "x": 0, "y": 2 },  { "_color":"blue", "x": 1, "y": 2 },  { "_color":"green", "x": 2, "y": 2 },  { "_color":"red", "x": 3, "y": 2 },  { "_color":"blue", "x": 4, "y": 2 },  { "_color":"yellow", "x": 5, "y": 2 },  { "_color":"yellow", "x": 6, "y": 2 },  { "_color":"green", "x": 7, "y": 2 }  ],[  { "_color":"green", "x": 0, "y": 3 },  { "_color":"green", "x": 1, "y": 3 },  { "_color":"yellow", "x": 2, "y": 3 },  { "_color":"green", "x": 3, "y": 3 },  { "_color":"blue", "x": 4, "y": 3 },  { "_color":"yellow", "x": 5, "y": 3 },  { "_color":"blue", "x": 6, "y": 3 },  { "_color":"red", "x": 7, "y": 3 }  ],[  { "_color":"yellow", "x": 0, "y": 4 },  { "_color":"yellow", "x": 1, "y": 4 },  { "_color":"red", "x": 2, "y": 4 },  { "_color":"red", "x": 3, "y": 4 },  { "_color":"red", "x": 4, "y": 4 },  { "_color":"red", "x": 5, "y": 4 },  { "_color":"green", "x": 6, "y": 4 },  { "_color":"green", "x": 7, "y": 4 }  ],[  { "_color":"red", "x": 0, "y": 5 },  { "_color":"red", "x": 1, "y": 5 },  { "_color":"blue", "x": 2, "y": 5 },  { "_color":"green", "x": 3, "y": 5 },  { "_color":"blue", "x": 4, "y": 5 },  { "_color":"red", "x": 5, "y": 5 },  { "_color":"yellow", "x": 6, "y": 5 },  { "_color":"blue", "x": 7, "y": 5 }  ],[  { "_color":"blue", "x": 0, "y": 6 },  { "_color":"blue", "x": 1, "y": 6 },  { "_color":"yellow", "x": 2, "y": 6 },  { "_color":"yellow", "x": 3, "y": 6 },  { "_color":"blue", "x": 4, "y": 6 },  { "_color":"blue", "x": 5, "y": 6 },  { "_color":"red", "x": 6, "y": 6 },  { "_color":"yellow", "x": 7, "y": 6 }  ],[  { "_color":"green", "x": 0, "y": 7 },  { "_color":"green", "x": 1, "y": 7 },  { "_color":"green", "x": 2, "y": 7 },  { "_color":"green", "x": 3, "y": 7 },  { "_color":"blue", "x": 4, "y": 7 },  { "_color":"green", "x": 5, "y": 7 },  { "_color":"red", "x": 6, "y": 7 },  { "_color":"blue", "x": 7, "y": 7 }  ],[  { "_color":"yellow", "x": 0, "y": 8 },  { "_color":"yellow", "x": 1, "y": 8 },  { "_color":"yellow", "x": 2, "y": 8 },  { "_color":"yellow", "x": 3, "y": 8 },  { "_color":"red", "x": 4, "y": 8 },  { "_color":"yellow", "x": 5, "y": 8 },  { "_color":"blue", "x": 6, "y": 8 },  { "_color":"yellow", "x": 7, "y": 8 }  ],[  { "_color":"red", "x": 0, "y": 9 },  { "_color":"red", "x": 1, "y": 9 },  { "_color":"yellow", "x": 2, "y": 9 },  { "_color":"red", "x": 3, "y": 9 },  { "_color":"red", "x": 4, "y": 9 },  { "_color":"blue", "x": 5, "y": 9 },  { "_color":"yellow", "x": 6, "y": 9 },  { "_color":"blue", "x": 7, "y": 9 }  ]      ]}';
  +  String firstViewTest = '{"_levelNum":1,"_levelTimeSec":120,"_requiredScore":30,"_comboHoldTime":2,"_blocks":[ "normalBlock" ],"_colors":[ "red","blue","green","yellow","black","purple" ],"_startField":[  [  { "_color":"red", "x": 0, "y": 1 },  { "_color":"red", "x": 1, "y": 1 },  { "_color":"blue", "x": 2, "y": 1 },  { "_color":"yellow", "x": 3, "y": 1 },  { "_color":"red", "x": 4, "y": 1 },  { "_color":"red", "x": 5, "y": 1 },  { "_color":"yellow", "x": 6, "y": 1 },  { "_color":"blue", "x": 7, "y": 1 }  ],    [  { "_color":"blue", "x": 0, "y": 2 },  { "_color":"blue", "x": 1, "y": 2 },  { "_color":"green", "x": 2, "y": 2 },  { "_color":"red", "x": 3, "y": 2 },  { "_color":"blue", "x": 4, "y": 2 },  { "_color":"yellow", "x": 5, "y": 2 },  { "_color":"yellow", "x": 6, "y": 2 },  { "_color":"green", "x": 7, "y": 2 }  ],[  { "_color":"green", "x": 0, "y": 3 },  { "_color":"green", "x": 1, "y": 3 },  { "_color":"yellow", "x": 2, "y": 3 },  { "_color":"green", "x": 3, "y": 3 },  { "_color":"blue", "x": 4, "y": 3 },  { "_color":"yellow", "x": 5, "y": 3 },  { "_color":"blue", "x": 6, "y": 3 },  { "_color":"red", "x": 7, "y": 3 }  ],[  { "_color":"yellow", "x": 0, "y": 4 },  { "_color":"yellow", "x": 1, "y": 4 },  { "_color":"red", "x": 2, "y": 4 },  { "_color":"red", "x": 3, "y": 4 },  { "_color":"red", "x": 4, "y": 4 },  { "_color":"red", "x": 5, "y": 4 },  { "_color":"green", "x": 6, "y": 4 },  { "_color":"green", "x": 7, "y": 4 }  ],[  { "_color":"red", "x": 0, "y": 5 },  { "_color":"red", "x": 1, "y": 5 },  { "_color":"blue", "x": 2, "y": 5 },  { "_color":"green", "x": 3, "y": 5 },  { "_color":"blue", "x": 4, "y": 5 },  { "_color":"red", "x": 5, "y": 5 },  { "_color":"yellow", "x": 6, "y": 5 },  { "_color":"blue", "x": 7, "y": 5 }  ],[  { "_color":"blue", "x": 0, "y": 6 },  { "_color":"blue", "x": 1, "y": 6 },  { "_color":"yellow", "x": 2, "y": 6 },  { "_color":"yellow", "x": 3, "y": 6 },  { "_color":"blue", "x": 4, "y": 6 },  { "_color":"blue", "x": 5, "y": 6 },  { "_color":"red", "x": 6, "y": 6 },  { "_color":"yellow", "x": 7, "y": 6 }  ],[  { "_color":"green", "x": 0, "y": 7 },  { "_color":"green", "x": 1, "y": 7 },  { "_color":"green", "x": 2, "y": 7 },  { "_color":"green", "x": 3, "y": 7 },  { "_color":"blue", "x": 4, "y": 7 },  { "_color":"green", "x": 5, "y": 7 },  { "_color":"red", "x": 6, "y": 7 },  { "_color":"blue", "x": 7, "y": 7 }  ],[  { "_color":"yellow", "x": 0, "y": 8 },  { "_color":"yellow", "x": 1, "y": 8 },  { "_color":"yellow", "x": 2, "y": 8 },  { "_color":"yellow", "x": 3, "y": 8 },  { "_color":"red", "x": 4, "y": 8 },  { "_color":"yellow", "x": 5, "y": 8 },  { "_color":"blue", "x": 6, "y": 8 },  { "_color":"yellow", "x": 7, "y": 8 }  ],[  { "_color":"red", "x": 0, "y": 9 },  { "_color":"red", "x": 1, "y": 9 },  { "_color":"yellow", "x": 2, "y": 9 },  { "_color":"red", "x": 3, "y": 9 },  { "_color":"red", "x": 4, "y": 9 },  { "_color":"blue", "x": 5, "y": 9 },  { "_color":"yellow", "x": 6, "y": 9 },  { "_color":"blue", "x": 7, "y": 9 }  ]      ]}';
     Level testLevel;
   
     /**
  
positive.code: 
    static const timerFieldUpDuration = const Duration(seconds: 4);
  
    static const timerFieldActionDuration = const Duration(milliseconds:  50);
  
    static const timerGravityDuration = const Duration(milliseconds: 300 );
  
    static const timerViewDuration = const Duration(milliseconds : 200);
  
    /**
     * Variables
  
negative.code:           _currentField.addCommand(new Command(Action.swap));
            break;
            //for debugging
          case KeyCode.ENTER:
            _currentField.addRow(testLevel.getBlocks(),testLevel.getColors());
            _currentField.timerFieldUp();
            break;
          case KeyCode.P:
            // toggle pause
  