iframe element Defines an inline frame (ie a frame embedded in a document), hgroup element The HTML Headings Group Element (<hgroup>) represents the heading of a section, nav element The HTML Navigation Element (<nav>) represents a section of a page that links to other pages or to parts within the page: a section with navigation links. These elements allows child elements from interactive, embedded, heading, sectioning, phrasing, and metadata content categories.
Click the html element name in the punctuation list to advance the example in 'Tryit-Editor':