 Second, he wrote "CoB" ("col Basso" – with the basses) in the lower stave of the piano part during "tuttis", implying that the left hand should reproduce the bass part.Sometimes, this bass was figured too, for example in the early edition of Nos.11–13 by Artaria in 1785, and Mozart and his father added figuration themselves to several of the concertos, such as the third piano part of No.