That technique is called 'pony ears' by some AFOLs, in reference to the 1x2 tile pushed onto a horse head in the good ol' days of brick-built horses (like...383 Knight's Joust). It's a technique that probably every kid who ever played with LEGO plates has done at least once, but TLG noticed that it "stresses the elements" and ceased to allow it in official sets. But the rule is not that simple; I've since been told it is illegal with plates but legal if you are using a tile, and I apologise that my memory fails to recall the reason... perhaps something to do with tiles being microscopically thinner, or the presence of the groove? Anyway, this is the first time I have noticed an official set using a panel for the technique. This perhaps suggests that the base of panels is the same thickness as a tile, especially given that panels do not have grooves.