Knit the plain needle to a certain position, and then adjust the stitches that need to be made into a figure of eight. For example, make an 8-pin 8-character,
Then, after knitting the sweater to a certain number of rows, use the other needle to put on the first four of the eight stitches that need to be made into a splayed shape, then knit four stitches, and then knit the first four stitches.