I'm working on my first proper Lightning Component project, and the experience has been both frustrating and pleasant. Pleasant in the sense that it reminds me of my days working with Flash and Actionscript, where you'd build movie clips (child components) with discrete animations or functionality, and they would dispatch events to listeners on the _root level/stage. (your parent, master component) The correlation is made all the more stronger since we're dealing with UI in both situations.

At any rate, this is a short post to talk about the Winter '17 lightning component, <lightning:icon />, and the recommended markup for UI components provided by the Lightning Design System (SLDS).