Today is Jackie Robinson Day around Major League Baseball. Robinson was the first African-American player to play in the major leagues; he started for the Brooklyn Dodgers on April 15, 1947, breaking the implicit “color line” in baseball. To honor him, all players, managers and coaches wear his uniform number 42 on this day.

So a question: Does each team have somebody operating a sewing machine (or farm out the job) to put “42” on blank uniform jerseys before the season starts? How does that work?