Looks to me like a corner got stuck in the machine and the bubble got squished several times until it freed itself.
I see no evidence of tire tread marks.
Tires aren't staight treaded.
https://www.google.c...iw=1024&bih=653
Lots of pressure,you can count the bubbles inside.
The lines aren't tire tread.
Black is either from rubber rollers or whatever.
They are probably from each time it got pressed/crushed before the sorter let go of it.
I count an easy 9 lines.Got stomped 9 times by the machine?
Picture the thumb as being the place the envelope was caught by.Trying to rotate out of the machine made a line each time it didn't clear the machine and continue down the line...
I'd bet whoever was supposed to be watching a machine either wasn't paying attention,caught the 5 Oclock rush or just came back from a 3 martini lunch break.
Pilot error...
Maybe they were at a Union meeting to get their piece of the latest price hike in postal fees...
From what I read,the rates HAD to go up NOT because it cost more to send stuff BUT because they aren't managing their $ properly.
They supposedly collect way more than it actually costs to mail stuff.
A lot of the $ just vanishes somewhere along the line.
They blame the internet by saying E Mail replaced letters.
I think the trade off of the increase in internet shipping of purchases equals things out in the long run.
I read the profit is higher to ship something than send a letter.
Especially since the are always decreasing services.
Then there are a LOT of people like me that would rather use $3.00 in postage instead of saving a couple cents or even a buck by putting more postage on something rather than spend 45 min. in line at the P.O. to send a SASBE or trade.
I've gotten stuff/bubbles that looked similar before.
Luckily the seeds weren't in the corner that got repeatedly squished.
