  We study a structure of subcategories which are called a polygon of
recollements in a triangulated category. First, we study a $2n$-gon of
recollements in an $(m/n)$-Calabi-Yau triangulated category. Second, we show
the homotopy category $\mathsf{K}(\mathsf{Mor}_{N-1}(\mathcal{B}))$ of
complexes of an additive category $\mathsf{Mor}_{N-1}(\mathcal{B})$ of $N-1$
sequences of split monomorphisms of an additive category $\mathcal{B}$ has a
$2N$-gon of recollments. Third, we show the homotopy category
$\mathsf{K}_{N}(\mathcal{B})$ of $N$-complexes of $\mathcal{B}$ has also a
$2N$-gon of recollments. Finally, we show there is a triangle equivalence
between $\mathsf{K}(\mathsf{Mor}_{N-1}(\mathcal{B}))$ and
$\mathsf{K}_{N}(\mathcal{B})$.
