On Mon, 22 May 2006 18:44:12 GMT, "JoeSpareBedroom"
wrote:

wrote in message
roups.com...
I'm referring to something that's not very deep though, like 1.5-2
inches. I thought they were there to hold up the concrete in high
traffic areas, and have nothing to do with slippage.


I don't know what their purpose is, but I've seen the end results.

Corner re-enforcement. Otherwise you need a radiused edge to
keep it from chipping off, and that's even worse.