Highcharts: Make the legend symbol a square or rectangle

Question

I am trying to Make the legend symbol a square or rectangle for a line graph. Example

Answer 1

You can make a fake series as follows and provider marker to it.

$(function () {
var chart = new Highcharts.Chart({
    chart: {
    renderTo: 'container',
    type: 'line',
    },
    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },

    plotOptions: {
        series: {
            marker: {
                enabled: true
            }
        }
    },
    legend: {
        layout: 'vertical',
        align: 'right',
        verticalAlign: 'middle',

        //borderWidth: 0
    },

    series: [{

        data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4],
        showInLegend : false,


        marker:{enabled:false}

    },{
        name : "testing",
        data : {},
        marker : {symbol : 'square',radius : 12 }
    }
            ]
});
});

Working demo : DEMO