長阿含經 10.p116

10.p116

“Without an inner perception of form, one observes external form to be blue. The blue form, blue reflection, and blue sight are like a blue lotus flower or a blue Vārāṇasī cloth. They are completely blue forms, blue reflections, and blue sights. Creating such a perception, one continuously observes and attends to it. This is the fifth change to the senses.