<div></div>

div { position:relative; background-color:#333;
      padding:20px; margin:20px; float:left;
}

div:before { content:""; display:block;
    padding:5px; background-color:#f60; border:2px solid white;
    position: absolute; top:-2px; right:-2px; border-bottom-left-radius: 10px;
}

var item = $('<span />');
item.click(function() { alert('click'); });
$('div').append(item);

div { position:relative; background-color:#333;
      padding:20px; margin:20px; float:left;
}

div span { content:""; display:block;
    padding:5px; background-color:#f60; border:2px solid white;
    position: absolute; top:-2px; right:-2px; border-bottom-left-radius: 10px;
}

var newDiv = $("<div class='orangeCircle'>");
$(".parentDivToOrangeCircle").append(newDiv);

.parentDivToOrangeCircle { position:relative; background-color:#333;
    padding:20px; margin:20px; float:left;
}

.orangeCircle {
    padding:5px; background-color:#f60; border:2px solid white;
    position: absolute; top:-2px; right:-2px; border-bottom-left-radius: 10px;
}

$("div").click(function(e){
    var $me = $(this),
        width = $me.outerWidth(),
        height = $me.outerHeight(),
        top = $me.position().top,
        left = $me.position().left;

    var len = Math.sqrt(Math.pow(width - e.offsetX, 2) + Math.pow(e.offsetY, 2));

    if (len < 10)
        alert('ding');
});​