private void HandleDrawing()
 {
     // screen released OR ballTouched event triggers.
     if (Input.GetMouseButtonUp(0) || ballTouchedEventTriggered)
     {
         // adapt curve to end at center of touched ball.
         if (ballTouchedEventTriggered)
         {
             InterpolateLine();
         }
         ballTouchedEventTriggered = false;
         firstTouchBall            = null;
         currentCursor.BeginLooping();
         EventManager.CallLooping();
         currentState = State.LOOP_LINE;
     }
     // black event triggers.
     else if (blackEventTriggered)
     {
         blackEventTriggered = false;
         currentCursor.DestroyCursor();
         EventManager.CallLevelRestart();
         currentState = State.AWAIT_INPUT;
     }
 }