of yarn and some knitting needles: either a pair of double-pointed needles (you do not need the entire set…just two), or a circular needle with any length cord and compatible gauge. i used a circular needle for the demonstration because i have the attention span of a fruit fly, and the last thing i need is to put down two double-points and wonder where they went when it is time to knit the next sock.
cast on four stitches. some patterns vary the number of cast-on stitches between three and five, so four is certainly acceptable. you can use pretty much any cast-on method you like, but keep in mind that 