This aggregate can itself be divided into fifteen: •1-4: the four causal forms, which are the four elements of earth, water, fire and wind. •5-9: the five sense objects of visual form, sound, smell, taste and texture. •10-14: the five sense faculties of eye, ear, nose, tongue and body. •15: the imperceptible form. This can further be subdivided into five: form of particles, spatial form, form resulting from a fully taken promise, imagined form and mastered form.