Granted Patent
Utility
US 4,409,750 · App. 06/293,902
Calender formed from a cube puzzle
Inventor:
Marvin A. Silbermintz
Patented Case
View Patent ↗
Granted: Oct 18, 1983
Filed: Aug 18, 1981
Inventor
Marvin A. Silbermintz
Assignee (at issue)
Ideal Toy Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.