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Multiple logarithmic spirals
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<iframe 
    src="https://jsxgraph.org/share/iframe/multiple-logarithmic-spirals" 
    style="border: 1px solid black; overflow: hidden; width: 550px; aspect-ratio: 55 / 65;" 
    name="JSXGraph example: Multiple logarithmic spirals" 
    allowfullscreen
></iframe>
This code has to 
<div id="board-0-wrapper" class="jxgbox-wrapper " style="width: 100%; ">
   <div id="board-0" class="jxgbox" style="aspect-ratio: 1 / 1; width: 100%;" data-ar="1 / 1"></div>
</div>

<script type = "text/javascript"> 
    /*
    This example is licensed under a 
    Creative Commons Attribution ShareAlike 4.0 International License.
    https://creativecommons.org/licenses/by-sa/4.0/
    
    Please note you have to mention 
    The Center of Mobile Learning with Digital Technology
    in the credits.
    */
    
    const BOARDID = 'board-0';

     var board = JXG.JSXGraph.initBoard(BOARDID, { boundingbox: [-12, 12, 12, -12], keepaspectratio: true });
    
     var a = board.create('slider', [[1, -1], [5, -1], [0, 0.3, 1]], { name: 'a' });
     var b = board.create('slider', [[1, -2], [5, -2], [0, 0.7, 1]], { name: 'b' });
     var tau = board.create('slider', [[-5, -3], [5, -3], [0, 0, 0.5]], { name: 'τ' });
    
     for (var i = 0; i < 8; i++) {
         // Use closures to define the 8 curves
         (function(x) { return board.create('curve', [
                (phi) => a.Value() * Math.exp(b.Value() * (phi + Math.PI * x * 0.25 + tau.Value() * Math.PI)), 
                [0, 0], 
                -4 * Math.PI, 8 * Math.PI],
                { curveType: 'polar', strokewidth: 1 }
             );
         })(i);
     }
    
 </script> 
/*
This example is licensed under a 
Creative Commons Attribution ShareAlike 4.0 International License.
https://creativecommons.org/licenses/by-sa/4.0/

Please note you have to mention 
The Center of Mobile Learning with Digital Technology
in the credits.
*/

const BOARDID = 'your_div_id'; // Insert your id here!

 var board = JXG.JSXGraph.initBoard(BOARDID, { boundingbox: [-12, 12, 12, -12], keepaspectratio: true });

 var a = board.create('slider', [[1, -1], [5, -1], [0, 0.3, 1]], { name: 'a' });
 var b = board.create('slider', [[1, -2], [5, -2], [0, 0.7, 1]], { name: 'b' });
 var tau = board.create('slider', [[-5, -3], [5, -3], [0, 0, 0.5]], { name: 'τ' });

 for (var i = 0; i < 8; i++) {
     // Use closures to define the 8 curves
     (function(x) { return board.create('curve', [
            (phi) => a.Value() * Math.exp(b.Value() * (phi + Math.PI * x * 0.25 + tau.Value() * Math.PI)), 
            [0, 0], 
            -4 * Math.PI, 8 * Math.PI],
            { curveType: 'polar', strokewidth: 1 }
         );
     })(i);
 }

<jsxgraph width="100%" aspect-ratio="1 / 1" title="Multiple logarithmic spirals" description="This construction was copied from JSXGraph examples database: BTW HERE SHOULD BE A GENERATED LINKuseGlobalJS="false">
   /*
   This example is licensed under a 
   Creative Commons Attribution ShareAlike 4.0 International License.
   https://creativecommons.org/licenses/by-sa/4.0/
   
   Please note you have to mention 
   The Center of Mobile Learning with Digital Technology
   in the credits.
   */
   
    var board = JXG.JSXGraph.initBoard(BOARDID, { boundingbox: [-12, 12, 12, -12], keepaspectratio: true });
   
    var a = board.create('slider', [[1, -1], [5, -1], [0, 0.3, 1]], { name: 'a' });
    var b = board.create('slider', [[1, -2], [5, -2], [0, 0.7, 1]], { name: 'b' });
    var tau = board.create('slider', [[-5, -3], [5, -3], [0, 0, 0.5]], { name: 'τ' });
   
    for (var i = 0; i < 8; i++) {
        // Use closures to define the 8 curves
        (function(x) { return board.create('curve', [
               (phi) => a.Value() * Math.exp(b.Value() * (phi + Math.PI * x * 0.25 + tau.Value() * Math.PI)), 
               [0, 0], 
               -4 * Math.PI, 8 * Math.PI],
               { curveType: 'polar', strokewidth: 1 }
            );
        })(i);
    }
   
</jsxgraph>
Eight logarithmic spirals defined by $$r = ae^{b\theta + k\cdot\pi/4 + \tau}\,.$$
// Define the id of your board in BOARDID

 var board = JXG.JSXGraph.initBoard(BOARDID, { boundingbox: [-12, 12, 12, -12], keepaspectratio: true });

 var a = board.create('slider', [[1, -1], [5, -1], [0, 0.3, 1]], { name: 'a' });
 var b = board.create('slider', [[1, -2], [5, -2], [0, 0.7, 1]], { name: 'b' });
 var tau = board.create('slider', [[-5, -3], [5, -3], [0, 0, 0.5]], { name: 'τ' });

 for (var i = 0; i < 8; i++) {
     // Use closures to define the 8 curves
     (function(x) { return board.create('curve', [
            (phi) => a.Value() * Math.exp(b.Value() * (phi + Math.PI * x * 0.25 + tau.Value() * Math.PI)), 
            [0, 0], 
            -4 * Math.PI, 8 * Math.PI],
            { curveType: 'polar', strokewidth: 1 }
         );
     })(i);
 }

license

This example is licensed under a Creative Commons Attribution ShareAlike 4.0 International License.
Please note you have to mention The Center of Mobile Learning with Digital Technology in the credits.