I found several patterns for isometric blankets, but they all used sc in the rhombuses.
I didn’t have much time to finish my blanket, so I made this pattern using dc.

You can use the yarn you prefer and a crochet hook that matches your yarn.

My blanket is 100 x 160 cm.

I used ca 9 balls of each colour.

Around the edge I crocheted a round of dc.

The pattern is also available in Norwegian.