The first image below has the lovely curve in the canal and the curve of the tree.
For the next image I looked specifically for curves that were man made. The building, the wheels of the bike. I found I could see curves everywhere.
A wet day not great for photos. Curves still on my mind. The curves of the railings on the bus and the S shaped curve that joins the people, following the line of the railing.
This image has the curves of the bollards leading from the man with the umbrella. The curve of the umbrella brings your eye up to the curve of the building leading out of the picture.