Wikipedia
The Konstruk-Tubes tubular building set was created in 2006 by Keith S. Lock of Bradenton, Florida. Keith Lock, a paramedic, invented the toy after seeing his children play with some PVC pipe and fittings.
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The basis of the set is simple, Polypropylene tubes and connectors. Lock added some unique designs to his connectors however. Basic shapes such as 90 degree elbows and Tee connectors are used, but more complex and specialized connectors are implemented as well, enabling a more diverse set of constructions than with just the simple shapes.
The toy has been accepted by the Manatee County school district in Florida and will be in every elementary school in that county.
Lockmade LLC. (based in Bradenton, Florida) owns the Konstruk-Tubes brand.