Flashing (weatherproofing) bark was occasionally used as a flashing material. Most flashing materials today are metal, plastic, rubber, or impregnated paper. Metal flashing materials include lead, aluminium, copper, stainless steel, zinc alloy, other architectural metals or a metal with a coating such as galvanized steel, lead-coated copper, anodized aluminum, terne-coated copper, galvalume (aluminum-zinc alloy coated sheet steel), and metals similar to stone-coated metal roofing. Metal flashing should be provided with expansion joints on long runs to prevent deformation of the metal sheets due to expansion and contraction, and should not stain or be stained by adjacent materials or react chemically with them.
I Don't Know What It Is Marius de Vries admitted that "I Don't Know What It Is" was one of the most complex production challenges he had ever faced, with its hundreds of layers of separate orchestral, choral, and vocal parts. Between "running around" and "chugging along" "on a train going God knows where to" in a sort of aimless wander, transportation is a major theme of the song. Wainwright alludes to several locations, from precise ones such as Calais, Dover, Poland and Lower Manhattan to more abstract locales like Heaven, Hell, and Limbo. Wainwright said the following of the song: References are also made to