Real easy pattern start and end colours when you run out of yarn. I tried to only change colours on the edges. If I have enough yarn, I'd do a square in that yarn. Some yarns I had enough to do several squares. Sometimes I'd knit every row, some squares were stockinette at the bottom, and when I changed yarns, changed to knit every row.
Mitred Square Scrappy Scarf
I used sock yarn and a 3mm circular 12 inch needle.
Cast on 43 stitches, Knit one row, purl one row.
1 - Knit 20 stitches, slip1, knit 2 together, pass slipped stitch over, knit to end
2 - Purl back
3 - Knit 19 stitches, slip 1, knit 2 together, pass slipped stitch over, knit to end
4 - purl back
5 - continue as for row 1 and 3, knit one less stitch before decrease.
When complete, leave last stitch on needle, pick up 21 stitches along edge of completed square. Using cable cast on, cast on another 21 stitches, 43 total stitches.
Continue as above until scarf is the desired length. Now .... I have tons of ends to darn in, and I will... I also decided that it needs some kind of edging. The sides are curling more than I had planned. I'm going to probably do a crochet edging. A little picot edging I think would look pretty.
As expected, I have more scraps left... so I started another lacy kind of scarf. But I haven;t gotten enough of it done to post a pic, plus I'll need to steam it before the lacy looks like lace, right now it doesn't.