a.k.a. Hexsticks, Notched Hexagonal Sticks
Patented by S. Coffin 1973, made by 3M 1970,
also discovered independently by B. Cutler.

(12 plastic pieces, 3.5 inches)

Three solutions for assembling the twelve notched sticks are described on pages 116-118 of Coffin's book. The package is shown above; it has the directions on the bottom (also shown above) and inside is a hexagonal shaped solution booklet. Below are two panels from each side (other three are shown on the next page):

Hectix Solution Pages Continued

Further Reading
Coffin Patent, from: www.uspto.gov - patent no. 3,721,448
Cutler's Hectix Page, from: http://home.comcast.net/~billcutler/stock/hectix.html
Cutler's Hectix Revisited Page, from: http://home.comcast.net/~billcutler/stock/revisited.html