U.S. toy company K'Nex said the discovery of a box cutter inside a container of Lincoln Logs was an isolated incident.

Josh Bulpitt said his three-year-old son received the LINCOLN LOGS building set as a gift from his aunt, but said he found a packing knife within a barrel that contained smaller parts of the toy.

Building and construction toys have been a fixture in playrooms since, well, forever, and there are several reasons for their enduring appeal.