A HUMBLE set of wooden shapes celebrates its 100th anniversary this year. Unit blocks, developed by early-childhood education pioneer Caroline Pratt in 1913, are wooden bricks, in carefully chosen ...
This media is in the public domain (free of copyright restrictions). You can copy, modify, and distribute this work without contacting the Smithsonian. For more information, visit the Smithsonian's ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results