When the director of our ad team, Lisa, tells me to try a new app, I know it’s going to be a good one. She has good taste. And this time it’s Brain Dots (for iOS and Android) which happens to be fun, challenging, infuriating, and sometimes totally deflating. But did I mention fun?

The premise of this series of increasingly difficult brain teasers is simple, even if the solutions aren’t: You try and draw a single line (or a series of lines) in a way that, when it drops to the ground, it will knock the pink and blue dots into each other.

 

Related: Alto’s Adventure: A beautiful app to cool you down on a hot day

If you’re the type who’s great at billiards, or geometry in general, this will totally be your bag. My kids happen to love it, and so do Lisa’s. As for me — someone who always scored lowest on mechanical ability and spatial relations in junior high achievement tests — well, it makes me crazy. Then again, it also makes me shriek every time I get an answer right before the third try, when the app will give you the answer. (Not that it’s always easy to do, even after you know the answer.)

Brain Dots app teaches geometry and spatial relations. And it's HARD!

Brain Dots: An awesome brain teaser app to teach spatial relations and geometry

A few things to note: You can earn coins or make in-app purchases to buy new pens but eh, I’m okay with the standard pencil. Plus recent updates mean there are ads-a-plenty, which can be super annoying — make sure your in-app purchases are locked down unless you want your kids downloading Game of War or the Lyft app.  I’d happy pay $.99 to get rid of them.

Related: Pay Once and Play: The best iOS games with no in-app purchases.

Also know that while the most basic drawing may look like a happy face, some of mine definitely look like boobs. It’s not intentional. (Ask Lisa!) So if you come up behind your kids and discover what looks like a major boob-drawing session, maybe they’re just innocently trying to solve a puzzle with two semi circles underneath two little dots.

Download Brain Dots free for iOS and Android, though there are in-app purchases. Make sure you download the one by developer Translimit, Inc, and not the knock-off developer that’s trading off their work. Boo.