zip2
.
((~)*.(<)*.zip2.(2π2//.(2π1)*,b_if(<,2π2,2π1)//.(2π2)*)o.++.(b_allvec[(id,id)o.2π2]o.(((id,(⁄)*.zip2.((2π2)*,(2π1)*)o)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o,-0.785398)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o,(!)*.zip2.((++)*.zip2.((b_allvec[(id,id)o.0.0]o)*.zip2.(zip2.(repeat.((((id,(⁄)*.zip2.((2π2)*,(2π1)*)o)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o,(2π1.2π2,b_if(<.(2π2.2π1,2π2.2π2)o,2π2.2π2,2π2.2π1))o//.++.(b_allvec[(id,id)o.2π2]o.(((id,(⁄)*.zip2.((2π2)*,(2π1)*)o)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o,-0.785398)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o)o,#)o,iota.#)o,(2π1.2π2,b_if(<.(2π2.2π1,2π2.2π2)o,2π2.2π2,2π2.2π1))o//.++.(b_allvec[(id,id)o.2π2]o.(((id,(⁄)*.zip2.((2π2)*,(2π1)*)o)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o,-0.785398)o,zip2.(id,id)o.(⁄)*.zip2.((2π2)*,(2π1)*)o)o)o,repeat.(id,#)o)o,iota.#)o)o