Superimposing the digital models and assigning each one a different color allows us to compare the real differences in depth and the changes from state to state. A composite overlay of Back (I) (in blue) and Back (II) (in yellow) demonstrates how the artist, starting with a new plaster cast of the first state, both carved into its surface and added fresh material to the body. What remains in blue demonstrates what Matisse generally retained from his first state.