This trivet shows a bubble pattern, which was adapted of a photograph. It resembles quite exactly the Voroni pattern, just with more rounded shapes. To get a little variety in trivet design I created a rounded square.
My build was done on a desktop cnc-machine by Stepcraft from 6 mm birch plywood using a spiral-toothed 1.2 mm flute. I used a very dark veneer (might have been ebony) on the topside.
A laser cutter might be a good alternative tool to create one like this.
Visit https://www.zenziwerken.de/en/Haushaltsgegenstaende/Topfuntersetzer for more trivet designs.
I used a random shot of a bubbles. Then I did some photoshopping to tune the details. Then I used Illustrator to trace the pixel image.