Thanks for your insightful comment. Our objective in this blab (= Web Lab) was a simple view into CS for the non-specialist, and so we were wary of getting in t

Thanks for your insightful comment. Our objective in this blab (= Web Lab) was a simple view into CS for the non-specialist, and so we were wary of getting in too deep with the various norms. And, frankly, a toy problem such as this omits a lot of important details. However, representing the l2 norm on the bar plot is a great idea. I'll look into that (BTW, you are free to edit, save & share the blab yourself if you wish.). For more detail you are welcome to visit "Intuitive Compressive Sensing" http://www.puzlet.com/m/b007z http://www.puzlet.com/m/b007z and "Compressive Sensing Primer" http://www.puzlet.com/m/b0080 http://www.puzlet.com/m/b0080 (these aren't blabs, and rely on server-side computation). In particular, there is an interesting plot in the first link showing the difference in norms.