I really like the pattern that is like chevron with a twist. You could use it on various items. It is made using single crochet and by changing the color according to the pattern below. X = 1 single crochet. Drop the yarn of the color you do not use to the back of the piece and pick it up when it is time to use that color. Make the color change in the last loop of a stitch.
In case you want a border around the pattern like on the laptop case here, I do recommend you to “cut” the pattern so that there are no long lines of the part of the pattern that is green in the picture close to the border. As you can see the green lines are at the most two stitches wide where they meet the border.
The starting chains is made in the color green. I have also made 1 single crochet of green at the start and at the end of each row. The rest of the border is made afterwards.
The pieces are attached to each other with reverse single crochet. The yellow line around the opening is made with cross stitches.
I have sewn a cotton fabric lining and put some insulating material between the lining and the crochet piece. The case closes with a zipper.