49 Brilliant Garage Organization Tips, Ideas and DIY Projects - Page 31 of 49 - DIY Crafts. This looks like Bouillon Cube jar lids screwed to the board, so jar part can screw onto the lid. I've also seen done with baby food jars.
This is a genius idea. A chair/ bench that can transform into a table, or both! This would be excellent to use in a smaller space where having multipurpose furniture is key to a functioning space. Or an outdoor space.