Sorry again, I must retract what I said about multiple line [php] scripts. I had forgotten to make my test page use the per-page RAW option. After checking that option, the [php] multiline example worked as expected.
If you really need a multiline [php] example not on a RAW page, you can actually define one using the [shortcoder] Plus option. You can use a [php] multiline example there. Same reason the other PHP plugins require defining the code in an admin page.
From the [php] documentation:
Important note: If your php code spans multiple lines (i.e., you use the Enter key), then you must use the HTML editor view, and check the Raw HTML per page option in the page/post editor screen. Short PHP snippets on just one line will work from either the HTML or Visual editors.
Just might be easier to use the snippet plugin I provided previously.