Help create an autoshape?

[hemmi1]

A guy at work showed me a spreadsheet where he created an "x" that is sized for a cell, and by his copying it, it'll resize to fit whatever cell he likes. One can type into the cell, and the 'x' stays, connecting the four corners of the cell. Please see the pic below. http://www.hemmi.us/temp.jpg
He went so fast that I couldn't see what he did to get that.
I tried autoshapes with no luck. This 'x' doesn't have a value, so that's why I think it's an autoshape.
He created the shape in a fraction of a second.
Any ideas? I really would like to use this. Googling has been no help, probably because I don't know what I'm looking for (Catch 22).
Thanks, Louis

How do I create this?

 

[lionpants]

- Right click the cell
- Choose "Format Cells..."
- Click the "Border" tab
- Click the button on the bottom left and click the button on the bottom right. (they look like forward and backward slashes)
- Click OK

 

[hemmi1]

I did not think of that, and was embarrassed to ask

It's amazing I can get sidetracked by such a small thing. I did right click and format cells, but it showed "General" and I did not think to look at the other tabs.

You have helped, believe me. THANKs