The Pilot Parallel Pen features a nib with two parallel plates. It is the key point for writers to create sharper lines than existing calligraphy pens. You can also use two Parallel pens to create blended colour lines by holding the pens vertically and touching one nib to the other nib. The colour from the top pen will be transferred to the bottom pen. The blending result will depends on how long you hold the pens together.