The triad is a specific form of tercet. The origins of the triad are Irish and Welsh. A triad is a poem composed of three tercets. It is a consideration of three things and their effect on a person. Welsh versions of the Arthurian legends make heavy use of this form.
Form: Enclosed tercets
Rhyme Scheme: aba bcb cdc
I often see what others see
Though seldom as they see it
I see instead that which might be.
On city sidewalks dimly lit
Chalk lines where children gather
Seem like a map unfinished yet.
Explanation seems a bother
My sight seems to me just fine
It's what I see that I prefer.