I have been trying to make a proper tartan scarf for quite a few years & without using crochet stitches afterwards, or, dozens of tiny balls of wool I haven’t managed it. This is the closest I have come up with & revolves entirely upon using 2 balls of exactly the same self striping yarn which have different start places in the colour sequence. For this I used some fabulous Lion brand Landscapes in coral reef colour way. It is It is aran in weight & 100%
acrylic, so, very soft. Luckily they put the colour sequence on the ball band, so it was easy to pick balls as far away in the colour repeat from each other as possible. You can usually check this online – even if you buy elsewhere. The pattern itself is simple, just make sure you count. If you offset the slipped stitch, you will get a brick pattern if you prefer.
4.5mm straight needles and 2 balls for a decent sized scarf