Each triangle has two back to back foils.
They can either be the same color or different colors.
This gives a bold streak to the hair. If the Wider base of the triangle is near the part the color will look bold up top. If the Wider base is faced towards the bottom, the color will be bold around the chin area, or cheekbone area.
Placement of these triangles can create so many different look.
Leave dark hair in between the triangles.