This pattern is an adaptation of my sister’s adaptation of a baby blanket. It makes a thick blanket that is great for cats to knead on and is lap-sized when laid flat, but fits into a cat carrier when folded in half. It is also a good size for small dogs. I wrote this up to make blankets for my local shelter that they can send home with new adoptees. I am using acrylic worsted weight yarn held double, but any combination of yarn that makes up roughly the same works as well (e.g. 2 strands of fingering is roughly equal to worsted weight; 2 strands of sport is a bit heavier – I just mix whatever I have). The only real criterion is that the blanket be washable so I only use acrylic.
You need about 16 ounces of yarn (450g) and US #13 needles (9 mm) to make up a blanket that is 20” by 24”.