I knitted these socks a couple of months ago. I used one striped yarn and one in solid colour (red). This is because sometimes when I knit man sized socks if run out of yarn before I am finished. I have started weighing the sock yarn that I have bought and found that it is not uncommon that they contain less than the stated 100 grams. So to avoid having to buy extra yarn I sometimes use two colours instead. it is also a great way to use leftovers from other sock projects.