div {
	column-width: 10em;
}

h4 {
	border: 1px solid;
	column-span: all;
}

Span test

It’s not often that you have to write a completely useless text that goes on for lines and lines. Still, I’d love to take up the challenge and see how quickly I can bore you. In the break tests we’ll be going to lengths to avoid a column break in this paragraph.

Heading

This is the second paragraph. We’ll try to break columns just before or after it.

Finally, in the third paragraph we continue our leisurely discussion of nothing in particular, so that we can see how the columns behave when text goes on and on and on.