P-Norm
From JSXGraph Wiki
The underlying JavaScript code
var brd = JXG.JSXGraph.initBoard('jxgbox', {axis:true, boundingbox:[-5,5,5,-5]});
var pNorm = brd.create('slider', [[0,4],[3,4],[0,2,10]], {name:'p'});
var m = brd.create('point',[0,0], {name:'M'});
graph = brd.create('curve', [
function(t){
var p = pNorm.Value();
return 2.0/Math.pow(Math.pow(Math.abs(Math.cos(t)),p)+
Math.pow(Math.abs(Math.sin(t)),p),1.0/p);
},
[function(){ return m.X();}, function(){ return m.Y();}],
0, Math.PI*2],
{curveType:'polar',strokeColor:'red', strokeWidth:2}
);