# Spirograph

From JSXGraph Wiki

### The underlying JavaScript code

```
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], keepaspectratio:true});
var R = 2.0;
var r = brd.create('slider',[[-3,4],[3,4],[-5,1,5]],{name:'r'});
var a = brd.create('slider',[[-3,3],[3,3],[-5,1,5]],{name:'a'});
var c = brd.create('curve',[
function(t){
var r1 = Math.round(100.0*r.Value())/100.0;
var a1 = Math.round(100.0*a.Value())/100.0;
return (R-r1)*Math.cos(r1/R*t)+a1*Math.cos((1-r1/R)*t);
},
function(t){
var r1 = Math.round(100.0*r.Value())/100.0;
var a1 = Math.round(100.0*a.Value())/100.0;
return (R-r1)*Math.sin(r1/R*t)+a1*Math.sin((1-r1/R)*t);
},
-40*Math.PI,40*Math.PI
], {strokeWidth:3, strokeColor:'#3355ff', strokeOpacity:0.7});
```