Many sidewalks and plazas in our area of Lisbon are paved with varying patterns of small black and white tiles.
Down our street, for example, a few address numbers are laid in the stones. We've also seen geometric designs, writing and flowers.
But the most mind-boggling arrangement we've seen were the tiles today at the Praça Dom Pedro IV, a flat surface visually contorted to hills and gulleys by the trompe-l'oeil layout of the individual light and dark pieces.
These photographs only capture a tiny part of the illusion of up and down space. To look at our feet while walking was highly disorienting! I felt like I should be stepping higher for the ridges, deeper for troughs -- and so worried about my miscalculations leading to tripping!
And seriously, this is a super flat surface. And looked at from specific angles, that is clear.