Thread

{exp:weblog:categories weblog="products" style="linear" parent_only="yes" show_empty="no"}
<h4>{category_name}</h4>

<p><ol class="order-form"><br />
    {exp:weblog:entries weblog="products" disable="member_data|pagination" dynamic="off" orderby="title" sort="asc" category="{category_id}"}<br />
    <li>{title}</li><br />
    {/exp:weblog:entries}<br />
</ol><br />
{/exp:weblog:categories}

{exp:weblog:categories weblog="products" style="linear" parent_only="yes" show_empty="no"}
<h4>{category_name}</h4>

<p>{embed="_embeds/.order-form" cat-id="{category_id}"}<br />
{/exp:weblog:categories}

<ol>
    {exp:weblog:entries weblog="products" disable="member_data|pagination" dynamic="off" orderby="title" sort="asc" category="{embed:cat-id}"}
    
    <?php $weblogCategory = "{categories limit='1'}{category_id}{/categories}";
        $category = "{embed:cat-id}";
        
    if($weblogCategory == $category){ ?>
    <li>{title}</li>
    <?php } ?>
    {/exp:weblog:entries}
</ol>