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.
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.