No arguments
      Description:
Compute the pointwise square function of selected images.
      Examples of use:
      • Example #1
      
 <a href="image.jpg" class="highslide" onclick="return hs.expand(this)">image.jpg</a> +sqr
                
Command: <a href="image.jpg" class="highslide" onclick="return hs.expand(this)">image.jpg</a> +sqr
        
Command: <a href="image.jpg" class="highslide" onclick="return hs.expand(this)">image.jpg</a> +sqr
               • Example #2
       300,1,1,1,'40*x/w+u' +sqr display_graph 400,300
                
Command: 300,1,1,1,'40*x/w+u' +sqr display_graph 400,300
        
Command: 300,1,1,1,'40*x/w+u' +sqr display_graph 400,300