var squareGrid = function setupGrid(_selection) {

    var instance = {};

    var square = 20,
        width = 900,  
        height = 300
        fill = '#130C0E', 
        stroke = '#FDBB30';  

    var dispatch = d3.dispatch('_hover');

    instance.render = function() {
        // calculate number of rows and columns
        var squaresRow = _.round(width / square);
        var squaresColumn = _.round(height / square);

        // create the svg
        var svg = d3.select(_selection).append('svg')
            .attr({
                width: width,
                height: height
            });

        // loop over number of columns 
        _.times(squaresColumn, function(n) {

            // create each set of rows
            var rows = svg.selectAll('rect' + ' .row-' + (n + 1))
                .data(d3.range(squaresRow))
                .enter().append('rect')
                    .attr({
                        class: function(d, i) {
                            return 'square row-' + (n + 1) + ' ' + 'col-' + (i + 1);
                        },
                        id: function(d, i) {
                            return 's-' + (n + 1) + (i + 1);
                        },
                        width: square,
                        height: square,
                        x: function(d, i) {
                            return i * square;
                        },
                        y: n * square,
                        fill: fill,
                        stroke: stroke
                    })
                    .on('mouseover', dispatch._hover);;

        });

        return instance;
    };

    instance.square = function(value) {
        if (!arguments.length) return square;
        square = value;
        return this;
    };
    instance.width = function(value) {
        if (!arguments.length) return width;
        width = value;
        return this;
    };
    instance.height = function(value) {
        if (!arguments.length) return height;
        height = value;
        return this;
    };
    instance.fill = function(value) {
        if (!arguments.length) return fill;
        fill = value;
        return this;
    };
    instance.stroke = function(value) {
        if (!arguments.length) return stroke;
        stroke = value;
        return this;
    };

    d3.rebind(instance, dispatch, 'on');
    return instance;
  
};