Pieter Bruegel the elder – Twelve proverbs  –
Antwerp, Museum Mayer van der Berg –
The Dutch inscription reads as follows:
Vat ick vervolghe en geraecke daer niet aen,
ick pisse altyt tegen de maen.
A somewhat more literal translation (contributed by Jan):
Whatever I pursue, I cannot reach it,
I keep pissing against the moon.
It essentially means “to waste one’s time on a futile endeavour”
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