Knitting patterns that have an odd number of rows are reversible when knitted flat. They are not well and truly reversible, since they will shift vertically the height of a row repeat. For many applications, though, they are practically reversible.
The simplest one: garter stitch.
Row 1: Knit. Repeat Row 1.
Row 1: Purl. Repeat Row 1.
Every odd-row pattern can be worked in two ways (this is true of any knitting pattern I can think of at the moment). As a matter of fact, to produce the same fabric with circular knitting, you must work them one way, then the other. The only way to detect which way a fabric has been knitted it to check the selvedges. Even then, you have no way of knowing whether the knitter knit it forwards (from left to right needle) or backwards (from right to left needle).
When graphing odd-row patterns I’m tempted to graph only one row repeat, but to be fair to circular knitters and to better represent the way the fabric looks, I think it’s better to graph two row repeats, but label the rows with the row numbers twice.
For the simplest example, to diagram garter stitch, I’m tempted to do this:
But I really should do this:
…which would still be read as knit every row when working flat, but is more faithful to the appearance of garter stitch. Also, the diagram tells me that I need to work every other row as purl when I knit circularly, since when I knit circular I read every chart row from the right.
The diagramming example is slightly ridiculous, since the graph doesn’t add much to the written directions. Diagrams are most useful to me when they condense long, elaborate directions into a clear graph of the knitting.
Next: what are some other 1-row patterns and how are they graphed?