# Amazing Math Tattoos!

6 x 9 = 42

Summation Tattoo

Complicated formula tattoo

Golden ratio tattoo

Silly math tattoo

Determinant tattoo

e^{i pi}+1 = 0

2^5 Tattoo

e^{i pi}+1 = 0

0/1 Matrix Tattoo

Physics Tattoo

Physics Tattoo

Knuckle Tattoo

e^{i pi}+1 = 0

Numbers Tattoo

Numbers Tattoo

### 20 thoughts on “Amazing Math Tattoos!”

1. That first one, 6×9=42 is not a mistake, but probably a reference to The Hitch Hiker’s Guide to the Galaxy, where Arthur Dent tries to work out the meaning to life, the universe and everything, with scrabble pieces.
He pulls the tiles out of a bag at random, and they spell out “what do you get when you multiply six by nine”. Since the correct answer is 42…

2. Yup… in the book the number 42 is The Answer to the Ultimate Question of Life, the Universe, and Everything, as calculated by an enormous supercomputer over a period of 7.5 million years.
wiki entry

3. In base 10, 6*7=42.
In base 13, 6*9=42.
Though I believe Douglas Adams said he wasn’t trying to write the joke in base 13.
The book did say 6*9, though.

4. The 6×9=42 is (as stated by others here) from the Hitch-hiker’s guide (the end of chapter 33 in the second book, the restaurant at the end of the universe, to be precise). The actual quotation from the text is:
“Arthur closed his eyes and plunged his hand into the towelful of stones. He jiggled them about, pulled out four and handed them to Ford. Ford laid them along the ground in the order he got them.
[…]
‘I, F,’ said Ford, ‘Y, O, U, … M, U, L, T, I, P, L, Y, … What do you get if you multiply, … S, I, X, … six, B, Y, by, six by … what do you get if you multiply six by … N, I, N, E, … six by nine …’ He paused. ‘Come on, where’s the next one?’
‘Er, that’s the lot,’ said Arthur, ‘that’s all there were.’
[…]
‘You mean that’s it?’ said Ford.
‘That’s it.’
‘Six by nine. Forty-two.’
‘That’s it. That’s all there is.'”
The quote is from the book by Douglas Adams and is copyrighted to either the late Mr. Adams, his family or the publishing company (I’m not really sure what happen with copyrights when the author pass away). The tattoo is, in my opinion, a nice way to pay homage to one of the best writers in all history.

5. The “silly math tattoo” is actually an expression in lambda calculus. It’s the fixed-point operator which is used for recursion.

6. The Y-combinator tattoo (the one with all the lambdas) has a misplaced closing parenthesis.
It should be lambda f . (lambda x . f (xx))(lambda x . f (xx))
Yes. I recognized and corrected something that only logicians and functional programmers have ever heard of…

7. Something told me “Biliga webbhotell” is a spammer :p
Seriously, is there really people crazy enough to get this kind of tatoos ? Are this non-permanent tattoos or photoshoping ?

8. Yup, this site gets about 10 spam messages a day. Whenever I increase the spam threshold, all the legitimate messages get marked as spam and the spam messages still make it through :-S
I think I’m going to have to look into some other options soon :-\

9. I’ll get the Laplace Transform in my arm… also the Inverse hehe… I’m studying Control Engineering…

10. Wintermute wrote:
“‘You mean that’s it?’ said Ford.
‘That’s it.’
‘Six by nine. Forty-two.’
‘That’s it. That’s all there is.'”
In the original BBC radio series, this is followed by …
“I always knew there was something fundamentally wrong with the universe.”
IMHO, this is perhaps the greatest punchline in the universe.

11. You didn’t recognise that the ‘Numbers Tattoo’ is actually the digits of pi (yeah, in order) starting on some part of the shoulder which is out of the photo? What’s the world coming to? On the second photo you can even see the bottom of the letter pi curving over his shoulder.
I think it looks pretty cool, with the varying digit sizes, although I wouldn’t waste an entire arm on a constant I can write with one letter. Unless I had a very small arm.
Also, I agree with Ben; there is no fail here. Oh, except he got the 221st digit of pi wrong. Just kidding; I don’t know enough digits of pi to check that.

12. well i guess the 6*9=42 may be reference to the math joke in which 69 means dinner for(4) two(2). ðŸ˜‰

1. IDK about all of these, but some of these are legit.
The dude with the knuckle tattoo, got that tat right after he received his degree in Mathematics. Failed “math failed.”