From the very first days of its home console business, Nintendo has given its box art a trademark standard, a border or frame that clearly marks the title as being for a Nintendo system. Did you know, though, that this trademark is a lot older than the NES or Famicom?
In the 1960s, Nintendo was busy making board games, many of which had some killer box art. Alongside that art, though, was a spine, a grey frame running down the left hand side of every box.
As Before Mario point out, the reason for this was simple: if Nintendo made good games, and put a giant mark on every box clearly labelling that game as coming from Nintendo, then the consumer would be able to look at a shelf, see the Nintendo games at a glance and know which ones to get.
It's a practice that the company stuck with during its board game years, adopted in the 1980s for its video game consoles and has retained ever since; even to this day the Wii U and 3DS have frames on every single game clearly showing they're for a Nintendo system.
Not that it was a Nintendo idea, mind you. While the company has innovated continually in the home video game space, in the '60s they weren't quite as pioneering; the idea to standardise their box art came straight from Milton Bradley, the company whose games Nintendo were licensing for the Japanese market.
You should check out the full breakdown on Before Mario, because it has even more of Nintendo's amazing board game box art.