columns and each character space with 5 punch positions. A 21 column card was comparable to the IBM Stub card. Mark sense format Mark sense (electrographic) cards, developed by Reynold B. Johnson at IBM, have printed ovals that could be marked with a special electrographic pencil. Cards would typically be punched with some initial information, such as the name and location of an inventory item. Information to be added, such as quantity of the item on hand, would be marked in the ovals. Card punches with an option to detect mark sense cards could then punch the corresponding information into the card. Aperture format Aperture cards have a cut-out hole on the right side of the punched card. A piece of 35 mm microfilm containing a microform image is mounted in the hole. Aperture cards are used for engineering drawings from all engineering disciplines. Information about the drawing, for example the drawing number, is typically punched and printed on the remainder of the card. Manufacturing IBM's Fred M. Carroll developed a series of rotary presses that were used to produce punched cards, including a 1921 model that operated at 460 cards per minute (cpm). In 1936 he introduced a completely different press that operated at 850 cpm. Carroll's high-speed press, containing a printing cylinder, revolutionized the company's manufacturing of punched cards. It is estimated that between 1930 and 1950, the Carroll press accounted for as much as 25 percent of the company's profits. Discarded printing plates from these card presses, each printing plate the size of an IBM card and formed into a cylinder, often found use as desk pen/pencil holders, and even today are collectible IBM artifacts (every card layout had its own printing plate). In the mid-1930s a box of 1,000 cards cost $1.05 (). Cultural impact While punched cards have not been widely used for generations, the impact was so great for most of the 20th century that they still appear from time to time in popular culture. For example: Accommodation of people's names: The Man Whose Name Wouldn't Fit Artist and architect Maya Lin in 2004 designed a public art installation at Ohio University, titled "Input", that looks like a punched card from the air. Tucker Hall at the University of Missouri – Columbia features architecture that is rumored to be influenced by punched cards. Although there are only two rows of windows on the building,