I initially didn't like the concrete prompt. Had no inspiration whatsoever. But then I came across this big concrete piece of art.

It's Kontinuität/Kontinuitaet/Continuity aka Koloss von Frankfurt by Max Bill (1986).

I like the geometric shape of this.

Max Bill "was keen on creating works based on mathematical and geometric foundations - material manifestations of intellectual processes that resisted symbolism."

source

I'm a bit proud of the end result. 😃