HI Artography - Abstract / What is this?

[Mike Lamb]

This might be a difficult one to guess.

28697

[Welmoed Sisson]

Looks like it needs to be rotated 90degrees clockwise.
My guess is that's an oil tank in an old basement, with corrosion from water leaking onto it.

[Mike Lamb]

Good job and close enough. It's a concrete ceiling leaking on a heat duct.

28698