This one was pretty cool and new to me. I'm not sure if I would have read it as how it works or as "Any one, but only one, of these, one or more times". (c

This one was pretty cool and new to me. I'm not sure if I would have read it as how it works or as "Any one, but only one, of these, one or more times". (cat|dog|bird){1,2} will match any of the following strings: cat dog bird catcat catdog catbird dogcat dogdog dogbird birdcat birddog birdbird Regardless, its pretty neat!