diff --git a/spec.txt b/spec.txt
@@ -4328,15 +4328,21 @@ the following principles resolve ambiguity:
12. An interpretation `<strong><em>...</em></strong>` is always
preferred to `<em><strong>..</strong></em>`.
-13. Earlier closings are preferred to later closings. Thus,
- when two potential emphasis or strong emphasis spans overlap,
- the first takes precedence: for example, `*foo _bar* baz_`
- is parsed as `<em>foo _bar</em> baz_` rather than
- `*foo <em>bar* baz</em>`. For the same reason,
+13. When two potential emphasis or strong emphasis spans overlap,
+ so that the second begins before the first ends and ends after
+ the first ends, the first is preferred. Thus, for example,
+ `*foo _bar* baz_` is parsed as `<em>foo _bar</em> baz_` rather
+ than `*foo <em>bar* baz</em>`. For the same reason,
`**foo*bar**` is parsed as `<em><em>foo</em>bar</em>*`
rather than `<strong>foo*bar</strong>`.
-14. Inline code spans, links, images, and HTML tags group more tightly
+14. When there are two potential emphasis or strong emphasis spans
+ with the same closing delimiter, the shorter one (the one that
+ opens later) is preferred. Thus, for example,
+ `**foo **bar baz**` is parsed as `**foo <strong>bar baz</strong>`
+ rather than `<strong>foo **bar baz</strong>`.
+
+15. Inline code spans, links, images, and HTML tags group more tightly
than emphasis. So, when there is a choice between an interpretation
that contains one of these elements and one that does not, the
former always wins. Thus, for example, `*[foo*](bar)` is
@@ -4970,6 +4976,20 @@ The following cases illustrate rule 13:
The following cases illustrate rule 14:
.
+**foo **bar baz**
+.
+<p>**foo <strong>bar baz</strong></p>
+.
+
+.
+*foo *bar baz*
+.
+<p>*foo <em>bar baz</em></p>
+.
+
+The following cases illustrate rule 15:
+
+.
*[foo*](bar)
.
<p>*<a href="bar">foo*</a></p>