This pattern is easily made larger by adding stitches to the foundation row. Since everything is pretty “straight”, there’s not much need for keeping track of how many foundation chains you start with as long as it is an even number to accommodate for the alternating between fphdc and bphdc, making sure when you begin the crotch section that you keep the same amount of stitches on each side, and adding rounds to the legs if needed to be longer.

As noted on the end of the pattern, I added some colored stripes to get a “team” look for a football set I was asked to make. I just front post single crocheted around the stitches of the rows and tried to keep things as straight as possible. No real magic there.