Sorry for the bad quality.
My grandfather had this in his office. He worked as a computer engineer so I initally thought it was a zoomed-in picture of a computer chip or something, but maybe it is something large.
He’s not alive anymore so I can’t ask him. If somebody can help me out, that would be great.
Could it be some kind of radiator or heat exchanger of a power plant?
https://www.indiamart.com/proddetail/compact-heat-exchanger-5364951488.html