What Is ^ Used for in Ruby? [Duplicate]

Possible Duplicate:
Use of caret symbol( ^ ) in Ruby

So I was playing around with some code and I tried to play around with the power operator. So I thought that perhaps I could use the caret (^) for this purpose, but after using it in:

for i in 0..10
  puts "#{i}   #{1^i}\n"
end

I got some really funky results

0   -  1
1   -  0
2   -  3
3   -  2
4   -  5
5   -  4
6   -  7
7   -  6
8   -  9
9   -  8
10  -  11

The only pattern I see is -1 on an odd number and +1 on an even number, but then when I try:

for i in 0..10
  puts "#{i}   #{2^i}\n"
end

i get:

0   -  2
1   -  3
2   -  0
3   -  1
4   -  6
5   -  7
6   -  4
7   -  5
8   -  10
9   -  11
10  -  8

wth! So then I kept going up to 4^i and plotted them, the 1^i & 3^i came out with decent patterns but 2^i & 4^i were just all over the place with no visible patterns (though highly unlikely) with just 11 plotting points, so I've come to you ladies and gents asking you:

What on earth is ^ used for?!