John:

Block quoting:

<blockquote> lorem ipsum etc yadda yadda </blockquote> gives

lorem ipsum etc yadda yadda

Italics:

<i>emphatic</i> gives emphatic

Bold: as with italics, but substitue ‘b’ for ‘i’, giving even more emphatic

Blank lines are paragraphs, or force a paragraph with <p/>.

Put in an actual ampersand & with ‘&amp;’ put in the angle brackets/ less-than/ greater-than with &lt; and &gt; respectively.

This looked correct when I previewed it, so if it goes wrong when I post it we’ve exposed a bug in Roger’s code.

I’ll leave it as an exercise for the reader to explain how I then coded this.