Apple on Thursday updated its App of the Week promotion with the game Yankai’s Triangle. For the next 7 days, you can pick up the triangular puzzler for free on both iPhone and iPad, a significant savings of $3.

From the App Store Editors’ Notes:

This deceptively simple puzzle game is pure Pythagorean pleasure. Rotating multicolored triangular puzzle pieces to snap them together with their mates is dead simple at first, but when layer after layer of triangles are in the mix, we truly come to respect the power of three. Bright hues and funny sound effects help seal the deal—you might even say it’s very acute.

And here’s a promo clip for the game:

Yankai’s Triangle is available in the App Store for free.