Knitting is such a fabulous technique, because the thread is given room to find and pursue its own course. This knit is only partially knit together on the upper- and under bar. Where it is tied off, the knit will curl.
On a flat-bed knitting machine the yarn, by means of a yarn feeder, is inserted into the needles and passes a needle bar from left to right and back. A bar is a metal surface with needles. On a V-bed knitting machine you have an upper- and an under bar.
You can also knit the yarn from the upper to the under bar thus creating a kind of circular knit.