Is it something like the following?
PHP Code:
function strok(){
O=document.getElementById('Q');
var ctx=O.getContext("2d");
ctx.fillStyle= '#996633';
ctx.strokeStyle = '#cc6633';
ctx.lineWidth = 4;
ctx.beginPath();
//start drawing COUNTER-CLOCKWISE.
ctx.moveTo(2,400); //top-left corner
ctx.lineTo(700,400); //the left surface
ctx.lineTo(900,650); //entrance floor
ctx.lineTo(1300,650); //hole floor
ctx.bezierCurveTo(1300,650,1360,600, 1355, 550); //curved cave ceiling
ctx.bezierCurveTo(1355,550, 1345, 500, 1325, 470);
ctx.bezierCurveTo(1325,470, 1200, 380, 1020, 480);
ctx.bezierCurveTo(1020,480, 1000, 520,975,570);
ctx.lineTo(850,400); //straight cave ceiling, back to the surface
ctx.lineTo(1375,400); //the right surface
ctx.lineTo(1375,715); //to bottom-right corner
ctx.lineTo(2,715); //to bottom-left corner
ctx.closePath();
ctx.fill();
ctx.stroke();
}