PI illustration display device

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Description

Within a transparent rectangle, balls illustrating the length of the circumference of a circle travel in hollow tubular channel.

FIG. 1 is an isometric view of the PI illustration display device.

FIG. 2 is a front view of the PI illustration display device.

FIG. 3 is a side view of the PI illustration display device; and,

FIG. 4 is a top view of the PI illustration display device.

Claims

The ornamental design for a PI illustration display device, as shown.

Referenced Cited
U.S. Patent Documents
4400162 August 23, 1983 Rustemis
5470234 November 28, 1995 Sher
5823783 October 20, 1998 Adams
6293800 September 25, 2001 Robertson
D474250 May 6, 2003 Herrera
D486183 February 3, 2004 DeMaison
7025593 April 11, 2006 Bauldock, Sr.
Patent History
Patent number: D531672
Type: Grant
Filed: Jan 4, 2005
Date of Patent: Nov 7, 2006
Inventor: Bruce Hannon (Champaign, IL)
Primary Examiner: Robert A. Delehanty
Assistant Examiner: Mark Cavanna
Attorney: Maloney, Parkinson & Berns
Application Number: 29/220,550
Classifications
Current U.S. Class: Demonstrator Or Exhibitor (10) (D19/62)