Gouache tubes and a "Chinese white" tube was added to boxes for this purpose. Later that century, for decorative uses "poster paint" was mass-produced, based on the much cheaper dextrin binder. It was sold in cans or as a powder to be mixed with water. The dextrin replaced older paint types based on hide glue or size. During the twentieth century, gouache began to be specially manufactured in tubes for more refined artistic purposes. Initially, gum arabic was used as a binder but soon cheaper brands were based on dextrin, as is most paint for children. A relatively new variation in
What Shall We Do Now? song is the same backing track as "Empty Spaces", but in the original key of D minor. It's a slow, dark progression with a repetitive, electronic drum beat and solo guitar, but where "Empty Spaces" ends and segues into "Young Lust", "What Shall We Do Now?" moves into a second, louder section punctuated with guitar power chords. The transition of D - E - F - E is a recurring theme throughout the album, heard on "In the Flesh?", "In the Flesh", "Waiting for the Worms", and the three "Another Brick in the Wall" songs. The long verse is played