This image depicts the interior of a classroom or lecture hall in Hayin Banki, Nigeria, devoid of people

This image depicts the interior of a classroom or lecture hall in Hayin Banki, Nigeria, devoid of people. A large, rectangular white whiteboard occupies the central portion of a light yellow wall, covered extensively with mathematical equations, symbols, and text related to Digital Signal Processing, including "DFT" and summations. Below the left side of the whiteboard, a white electrical wall outlet is visible, from which a white charging cable extends downwards, resting on a raised concrete platform. Two dark, cylindrical objects, possibly markers or parts of a charger, lie near the end of the cable on the platform. The platform, constructed from light-colored concrete blocks, rises from a tiled floor with light brown square tiles. Above the whiteboard, a horizontal white trim strip runs along the wall, bearing a circular sticker with the number "14" and a faint inscription "SFFS03/0". The ceiling consists of white suspended ceiling panels with a visible grid structure.