g);
}

var bindClickEvent = function(expectedDirection){
  // get the current and initial coords of the circle and reward
  // agent based on directive
  d3.select('#subbtn').on('click', function(){
    var currentCircle = d3.select('circle')[0][0];
    var currentCoords = shapes.gridCoords(currentCircle);
    var initialCoords = currentCircle.getBBox();

    var dragged = false;
    if(expectedDirection === 'up' && currentCoords.y < initialCoords.y) dragged = true;
    else if(expectedDirection === 'down' 