用canvas绘制图形！！！

哪位帮忙画下“▶”“ ◀”这两个图形！

[code="html"]
<!DOCTYPE HTML>






<br> var c = document.getElementById(&#39;myCanvas&#39;);<br> var cxt = c.getContext(&#39;2d&#39;);<br> cxt.fillStyle = &quot;#000000&quot;;<br> cxt.moveTo(0,0);<br><br> cxt.lineTo(0,100);<br><br> cxt.lineTo(100,50); <br> cxt.fill();<br> //<br> cxt.moveTo(200,0);<br><br> cxt.lineTo(200,100);<br><br> cxt.lineTo(100,50); <br> cxt.fill();<br>

[/code]