Hoping For A Date From Envelope Or Content

Trying to date this item and was hoping there's something on the envelope that dates it that I'm not aware of.
I believe the 3 cent stamp called for would mean it's some time between Apr.15th 1915 to Jul. 1st 1926 or Jul. 1st 1931 to Apr. 1st 1943.
If I'm correct these are the time frames of when the cost of mailing was 3 cents.
Research indicates that the company set up in this location I believe around 1924 so it could be from either time frame.
Can anyone see anything here that could help in the dating?

The eye trick with the cubes is interesting, it took me a while and several attempts to finally see it.

Cheers, Bill

Maybe 1918..?

Robert

http://vintagemachinery.org/mfginde...aspx?id=1156

http://buzzcoil.brinkster.net/petrie/000index.html

Thanks Wert, I've been on those sites and in contact with one of the site owners..
I can't find information on Petrie's location in 1918.
The company ran into financial troubles in 1922-23 and Lister from England took them over.
I believe it was 1924 they announced the headquarters would be at the address on the envelope. But was it a change of address?

How many cubes did you see?

Cheers, Bill

I see 7

Robert

But really 13

There are 24 diamonds, of course... no cubes

No cubes...???

Interestingly, I find that card extraordinary, in promoting a product.
Originally I see the white cubes with black tops,
when I look at the advert, then back to the cubes, I see the white cubes with
black bottoms.

An advertising masterpiece.

Wert. A cube is 3D. The paper is 2D. Your brain is fooling you. Too much fly-specking.

Rod

I agree, turn it upside down and the cubes change..Kinda neat.

Robert


Sak...good one buddy..haha

My thoughts are the same as rod222.
I thought it was brilliant.

Cheers, Bill