This pattern is worked back and forth on a multiple of 9 stitches. Changes for circular knitting follow.
Cast on 9 stitches per repeat (that is, per triangle desired).
Row 1: *ssk, k5, k2tog, yo; repeat from *, omitting final yo.
Row 2: purl, working (p1, k1) in yo.
Row 3: *ssk, k3, k2tog, (yo, k1) twice, yo; repeat from *.
Row 4: purl.
Row 5: *ssk, k1, k2tog, (yo, k1) 5 times, yo; repeat from *.
Row 6: *p3, k 11; repeat from *.
Row 7: *sl 1, k2tog, psso, yo, k 11, yo; repeat from *.
Row 8: bind off loosely.
One warning: the natural shape of the scallop is wider than necessary to produce the scallop. Unblocked the pattern will produce a wavy bell ruffle--which may be what you want! If blocked flat it will want to curve, as shown in the photo below.
Note: you can work rows 7 and 8 in a contrasting color to emphasize the scalloped edge. Descriptions for knitting a circular band and for knitting a bookmark follow.
To work this edging in the round, cast on 9 sts per repeat, bring the ends together and knit one round to establish the circle. Follow instructions for the back-and forth version with the following changes: On Round 1, do not omit the final yo. On even numbered rows, knit where it says purl and purl where it says knit. Bind off by purling rather than knitting.
The bookmark was made in the round, and seamed down the center. Cast on enough stitches for an even number of repeats, plus four stitches. Knit one round plain, then follow the pattern above. On Round 1, work half the repeats as described above (ending yo), then k1, yo, k1, yo, then the other half of the repeats, k1, yo, k1, yo. In each of these extra YOs you will work an extra scallop to make the 3/4 circle on each end. Whipstitch the center seam, carefully matching the two sides (which I didn't do so well in the first attempt shown in the photo...)
©Judy Gibson, 2002. Permission granted for any use you like, as long as credit is given in any published patterns to me as designer of the edging.
Judy Gibson, Descanso, California.