ctx.moveTo(x,y);

context.arc(x, y, radius, i*pieAngle, (i+1)*pieAngle, false);

// size of a pie : it is an angle in radians
var pieAngle = 2 * Math.PI / hours;

var hueValue = i * 15;
    context.fillStyle = 'hsl(' + hueValue + ',70%, 60%)';

function drawSegments(radius) {
    for (var i = 0; i < hours; i++) {
        context.beginPath();
        context.moveTo(x, y);
        context.arc(x, y, radius, i*pieAngle, (i+1)*pieAngle, false);
        context.lineWidth = segmentDepth;
        var hueValue = i * 15;
        context.fillStyle = 'hsl(' + hueValue + ',70%, 60%)';
        // '#'+(Math.random()*0xFFFFFF<<0).toString(16);
        context.fill();
        context.lineWidth = 2;
        context.strokeStyle = '#444';
        context.stroke();
    }
}