rotate[1] is a verb that rotates an array y by the number of elements given in x.
y
x
Positive x rotates left, and negative x rotates right.
2! 1 2 3 4 5 6 7 3 4 5 6 7 1 2 -2! 1 2 3 4 5 6 7 6 7 1 2 3 4 5