"Spin4 example"
"author : afmika"

"This program swaps the top value of the stack"
(+03<5>)      "rotate while accumulating using addition"

"swaping values is easy"
xy            "push x, x to the stack ie. stack := -1 1"
[xy]          "pop the 2-first top values to the accumulator respectively in the component x and y"
xy            "push x, y to the stack (now reversed, stack := 1 -1)"