Instead of brush strokes, Hervis uses the natural grains of wood, which differ in color, density and texture. When he needs other colors, he stains the wood by immersing it in vegetal dye for a few months. Though he has worked with exotic wood from Brazil and Africa, Hervis does not use too diverse a range on one piece, and his favourite types include walnut, cherry tree, sycamore, mahogany and maple. These are cut into the desired shapes, one millimetre thick, and fitted together like a jigsaw and glued onto a wooden "canvas". The piece is then vacuum pressed to ensure binding, and the surface is sanded down to evenness.