Maybe you saw Data|subtotals in action--or Data|Group and Outline???

Both of these will show the outlining symbols to the left of the worksheet.

Exasperated and Requiring Assistance wrote:

I know how to hide / show the rows, but how do it so as to leave a little
plus sign in the corner that allows me to control the number of rows to
expand / contract (and I know you can do it - I've seen it on other
spreadsheets!)

--

Dave Peterson