This is Just to Say by William Carlos Williams

I have eaten
the plums
that were in
the ice box

and which
you were probably
saving
for breakfast.

Forgive me
they were delicious
so sweet and so cold.

On a wall in The Hague.
For more on this poet and his poems, click on these links:
https://en.wikipedia.org/wiki/William_Carlos_Williams

https://www.poetryfoundation.org/poets/william-carlos-williams