customDraw() {
        var ctx = simulationArea.context;
        ctx.beginPath();
        ctx.font = '20px Raleway';
        ctx.fillStyle = colors['input_text'];
        ctx.textAlign = 'center';
        fillText(ctx, this.state.toString(16), this.x, this.y + 5);
        ctx.fill();
    }
@memberof Stepper
function to draw element