User blog comment:J. Severe/The Simpsons LEGO Spectacular/@comment-3398859-20140428204739/@comment-1518158-20140429190959

Speaking of which, the people working on this ep said that they managed to sneak in a ref to The LEGO Movie at the last second after seeing it, so I wouldn't be surprised if saw Milhouse being a master builder being alluded to in this.