Dear twinpictures,
Thank you very much for the helpful and prompt reply to my question which was just what I needed. You might add this additional fact (that the block you must use is the shortcode block, which is found under the widgets section of blocks) to the Collapse-o-matic section of our WP software widgets section. Understanding this necessary step would be helpful to people who are using Collapse-o-matic for the first time. Collapse-o-matic is quite a useful plugin making long articles much more accessible. Thanks!
