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.