Aha! I knew these guys would eventually open a restaurant, but I always imagined it would be a joint venture, not next-door competing eateries. Found at Google Street View, ever the source for coincidence, not irony. This is in Manchester, United Kingdom, where reports of plumbing failures have peppered the news there.
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Mario's is a bakery. Luigi's is a kebab joint (though they serve other food as well, I'm told). Not much in the way in the way of direct competition, unless some kid can't decide between cake or birthday kebabs (which may or may not have come up when I lived there).