So-called “STEM learning” toys abound in the marketplace nowadays. Why hand your kid a Slinky when you can offer her something that purports to totally turbocharge her future earning potential growing brain?

Whether or not you believe that kind of hype, the trouble with many of these toys is that they seem overthought and under . . . funned. Take this robot: it looks cute and kinda cool, and you can program it, I guess? But it doesn’t seem to invite the kind of open-ended world-building that the best “educational” toys do. Let’s face it: there’s a reason why good old-fashioned Lego blocks get passed down from generation to generation.

Which is why the best feature of Mabot, a STEM-learning robot-building kit featured on OGadget, might be its least flashy: it’s compatible with the Lego bricks your kid most likely owns (and loves) already.

Sure, Mabot has other cool-looking stuff going for it. Its spherical pieces—inspired by those ball-and-stick models of molecules you may remember from science class—immediately suggest off-label ways to play that the designers may not have intended. (My daughters would probably try to bowl with them, as well as build.) It comes with brainy-sounding add-ons, like an app that lets you control your Mabot from a smartphone, as well as a colorful visual programming language that looks heavily inspired by MIT’s Scratch.

But the fact that kids can just stick their Legos onto Mabot and make them seem new again? That’s genius. My kids constantly mix and match their toys—they never stay in one play-world for long. Instead of setting Mabot up as yet another single-purpose “educational” plaything siloed away from the rest, the Mabot team tells Co.Design that they see their creation as “an extension part” for other toys. “Many kids love Lego and it is already in so many homes,” they wrote via email. “We want to increase their fun and bring more creativity for the children.”

Of course, you could just buy Lego Mindstorms—a robot-building kit that, obviously, also works with those beloved blocks. But Mabot’s kit is $150 cheaper. That’s a significantly lower barrier to clear for cost-conscious parents eager to get their kids on the STEM train. But to be honest, Mabot just looks more fun than Mindstorms. The round, brightly-colored pieces look friendly and unintimidating (but not babyish) compared Mindstorms’ sharp-edged, technical-looking components. Mabot looks like something you could dump out on the floor with your kids on a whim; Mindstorms looks like you’d need to send them to a vocational college first.

Don’t get me wrong. I’m a Lego devotee. And that’s why Mabot seems so appealing to me as a parent, on an almost gut-instinct level. It’s an educational toy whose design says “and,” not “but” or “either/or.” Would it make my daughters want to be engineers when they grow up? Who cares? If it invites them to color outside the lines in life—and in their own toy collections—I say: mission accomplished.