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Patent
D531672
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Priority
Jan 04 2005
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Filed
Jan 04 2005
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Issued
Nov 07 2006
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Expiry
Nov 07 2020
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Assg.orig
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Entity
unknown
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6
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7
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n/a
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The ornamental design for a pi illustration display device, as shown.
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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.
Hannon, Bruce
Patent |
Priority |
Assignee |
Title |
4400162, |
Apr 05 1982 |
|
Planetarium |
5470234, |
Jun 16 1993 |
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Circular, piece-matching math educational aid |
5823783, |
Jun 14 1995 |
|
Rotating pie graph: mathematics learning tool |
6293800, |
May 13 1999 |
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Educational and entertainment device |
7025593, |
Nov 20 2003 |
Gerald, Bauldock, Sr. |
Teaching circumference instrument |
D474250, |
Nov 29 2001 |
|
Solar system toy |
D486183, |
Jan 09 2002 |
|
Coin teaching set |
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