The hidden date for this stamp can be found in the bottom-right corner.
Many Canadians innovations in the field of transportation arose to meet the demands of the Canadian environment. In 1869, Dr. J.W. Elliott, a Toronto dentist, invented the rotary snowplow to keep railways operating during Canadian winters. Reflecting the importance of aviation in such a vast country, Wallace Turnbull of Rothesay, New Brunswick, invented the variable-pitch propeller in the early 1920s, and Dr. Wilbur Franks of Toronto invented the anti-gravity flight suit in the late 1930s. Canadians have also embraced space technology, as can be seen by the development of the Canadarm by the National Research Council and Spar Aerospace Ltd. The stamp designs by Roger Hill of Toronto show a blueprint of each innovation, highlighted with colour, and a small illustration of each invention as it was originally used.