Whiteboard
Whiteboards became commercially available in the early 1960s, but did not become widely used until 30 years later. Early whiteboards needed to be wiped with a damp cloth and markers had a tendency to leave marks behind, even after erasing the board. Dry-erase markers for whiteboards were invented in 1975.
Coin board
The coin collecting board was invented in 1934 by Joseph Kent Post, an engineer with Kimberly-Clark in Neenah, Wisconsin. His knowledge of paper products and their manufacture, combined with his interest in coin collecting, prompted him to devise this inexpensive means to collect coins. Debuting early in 1935, his first coin boards (one each for Indian Head and Lincoln Cents) were priced at 25 cents retail, and these quickly proved successful. Sold at newsstands, stationery stores, 5-and-10-cent stores and similar retail outlets, coin boards were the point of entry for thousands of new coin collectors between 1935 and 1942, when most publishers discontinued them in favor of the more convenient coin folders still used today. Post marketed his coin boards under the brand name Kent Co. Coin Card, but later in 1935 he sold his invention to Whitman Publishing Company of Racine, Wisconsin, which was already a leading producer of puzzles, games and other paper novelties. Whitman became the most prolific of coin board producers and had the most extensive list of coin series titles.