Impress your neighbors!
Protect yourself from invading thieves and vandals!
Protect the borders of your property from unwanted salespeepo!
http://www.docsmachine.com/nonPB/mortar.html
yeah, I know, it wouldn't work in japan....but it'd be kind of funny with all the other crazy things people are doing these days in good ol' nippon....
Notice the cannonball dent in the side!
Got 'em!