The Oak Leaf is a fun little introduction to stacked decreases. This technique can be used to create lobe shaped edging, flame stitch motifs, and shaping. You may have seen it in other patterns like Fox Paws which use the wavy stitch in colorwork. Stacked decreases are worked by slipping stitches back to the left needle to work them again.

Finished Size: Approx. 6” (15 cm) wide and 4” (10 cm) long.
Yarn: Approx. 10 yards (9.5 m) of worsted weight yarn.
Needles: Size 10 (6mm) needles, or one size up from size on label.
Gauge: Not essential.
Other Materials: Sewing needle, steamer, blocking surface, pins.

For a video showing how to do the decreases in this pattern, follow this link.
This article will help if you want to use stacked decreases in other projects.