Spin phase–resolved NuSTAR spectroscopy of OAO 1657–415 for 16 phase bins. From top to bottom are the normalized intensity of the pulse profiles, absorption column density N_H2 (in units of 10²² cm⁻²), covering fraction f, Fe Kα normalization (Fe_norm; in photons cm⁻² s⁻¹), spectral index Γ, normalization of the power law (Γ_norm; in photons keV⁻¹ cm⁻² s⁻¹ at 1 keV), and folding energy (E _fold; in keV). The corner plots of the third, seventh, and 13th phase bins, where the absorbing column density is low, high, and medium, respectively, are shown in Figure A5, A6, and A7.