This example shows how complex you can make your knot appear without much effort. Just by adding more walls to it you can get a variety of patterns. Here I have also made my knot fill an area other than a square. To do this, I simply marked off the appropriate area on my graph and proceeded as usual. All the other steps will remain the same when you make you knots fill unusual shapes, although you may have to change the shape of your "elbows" in some cases, like when you are filling a circle. Your normal "elbows" will not fit within the circle shape cleanly and you sometimes have to jimmy it around a bit to make it look nice.
This example is again within an unusual shape. As before, all you need to do is mark off the desired area on your graph paper and then continue with your criss-crossing and elbows, and corners, as you normally would. It is useful to practice making these knots because they are very helpful when you have an odd space to fill in your artwork.