http://www.w3.org/TR/css3-box/#display

This paragraph contains several 'span' elements that should not be seen. [Like this one.] Each is enclosed by square brackets [(like this!)] to help note where they are located. [If you can read this, you should be viewing source.]

This is one of three paragraph elements.

They should run together as inline content.

If they look like normal paragraphs, there is a problem.

This is one of three span elements.

They should generate block boxes.

If they look like normal spans, running together as inline content, there is a problem.

This is one of three paragraph elements.

They should sit next to each other as inline boxes.

If they look like normal paragraphs, there may be a problem.

This is one of three span elements.

They should appear to be list items in a list, either ordered or unordered.

If they look like normal spans, running together as inline content, there is a problem.

A run-in.

This is a paragraph element preceded by a 'strong' element. The 'strong' should be inserted into the beginning of the paragraph as a run-in element. If it is above the paragraph, there is a problem.

A run-in element which is much longer than the previous example of a run-in element, included to distinguish its behavior from a floated element. As discussed, it should be inserted into the following block element.

This is a paragraph element preceded by a 'strong' element. The 'strong' should be inserted into the beginning of the paragraph as a run-in element. If it is above the paragraph, there is a problem.