These waves have some spiky bits for variety.
The wallpaper version is available at the preceding link.
Today's Gratitude Item: A simple solution to an annoying problem. There is a sink outside my classroom which is convenient for filling my water bottle. There was also a kettle near said sink and some of our students used to boil water to make instant noodles. Problem was that sometimes they would leave a disgusting mess where noodles would end up blocking the sink. The solution? Remove the kettle. This means no nasty noodles in the sink and some very happy seniors who needed a second kettle for their common room.