Igor Stravinsky (1882 - 1971), the famed Russian composer, invented this little dynamo so he could generate staves anywhere, anytime. Using a combination of the first part of his last name (Strav-) and his first name (-igor), he named it the Stravigor. Nikolai von Struve (1876 - 1920), a friend, attempted to patent it for Stravinsky just before WWI in 1911, which never happened.
The Stravigor evolved from a 5-pointed pen called a rastrum, but instead of fixed points, the Stravigor utilized rollers. With its two-sided design, users could acquire one with a combination of single, double and wide rollers (double-roller example at bottom of page). Pads were located within the housing which the rollers brushed against for inking. A pair of snug fitting caps prevented the rollers from staining one's pockets.
Most people that find one of these don't know what it is unless they are familiar with stavewriters. Finding an original Stravigor, or accurately marketing one for sale, is very difficult because they have no identifiers. The only markings read "Made in U.S.A." on one side and "Pat. Apld. For" on the other. Neither the inventor's name nor the name of the invention are anywhere on the tool.
Though a patent was never actually awarded for the Stravigor, they were obviously still produced, albeit in small quantities, and decades later reproductions were brought to market. Igor Stravinsky used his quite often during the rest of his career.