Vandyke stitch is a very decorative way to fill a set of parallel lines in a pattern. It creates a plaited effect down the centre of the pattern.
It can be helpful to begin by drawing two parallel lines on your fabric to keep the width of your stitches an equal distance apart.
Firstly, bring the needle up near the beginning of your first line, just a little way along, as shown in the picture on the left. Insert the needle horizontally in between the two parallel lines further up near the starting point of the pattern and draw the needle through to make a small horizontal stitch.
Push the needle in through the front of the fabric on the line opposite to the starting point of your original stitch, bringing the needle back up again just below the starting point of your original stitch.
Draw your needle and thread through. Pass the needle behind the crossed threads in the centre without piercing the fabric and pull the thread through.
Push your needle back into the fabric on the right hand line, just below the start of your previous stitch and bring the needle back up just below the start of the last stitch on the opposite line, as shown below. Draw your thread through.
Again, pass the needle behind the crossed threads in the centre without piercing the fabric and pull the thread through.
Continue the pattern along the parallel lines in the manner described above.
You can continue to make the pattern as long or as short as you want it!