Elsie Sticks were plastic ice cream sticks which became useful as an interlocking toy after the ice cream bar was eaten. They were produced in the early 1970s through Borden, Inc., dairy in the United States.
Historically, Elsie Sticks appear to have emerged in the 1950s with U.S. Patent 2,844,910 a construction kit made of wooden ice cream sticks by the Southern Ice Cream Company of Kansas City, MO. This patent was extended in 1972 with U.S. Patent 3,663,717 and U.S. Patent 3,748,778. The new toy design utilized plastic and modified the interlocking stick design.
Elsie Stix were very portable and collectable. Finding Elsie Stix now is very difficult.
Controversy
Supposedly, Theora Design from Israel, claims to have invented Elsie Stix under a different name. The name of their sticks were Icetix and they were distributed into the US through Borden Dairy.