cable stitch. The size of the needle is one of the constants to diminish the variables in figuring out the size. Here's two pics. The intricate design included an increase of 20 stitches, while the minimalist only required the increase of 5 stitches to maintain the 12x12 size.

Stick with it, brioche is beautiful. Love the colors! Here's a wedding blanket I made for my niece and her partner:

Molly and I are new to BlueSky. #dogsofbluesky