build_wither

local ws = {
    skull = 1,
    sand = 2,
}

function ws.strafe_left(n)
    turtle.turnLeft()
    for i=1,n do
        turtle.forward()
    end
    turtle.turnRight()
end

function ws.strafe_right(n)
    turtle.turnRight()
    for i=1,n do
        turtle.forward()
    end
    turtle.turnLeft()
end

function ws.build_wither()
    turtle.select(ws.sand)
    turtle.down()
    turtle.down()
    turtle.forward()
    turtle.forward()
    turtle.down()
    turtle.down()
    turtle.place()
    turtle.up()
    turtle.place()
    ws.strafe_right(1)
    turtle.place()
    ws.strafe_left(2)
    turtle.place()
    turtle.up()
    turtle.select(ws.skull)
    turtle.place()
    ws.strafe_right(1)
    turtle.place()
    ws.strafe_right(1)
    turtle.place()
    ws.strafe_left(1)
    turtle.back()
    turtle.back()
    turtle.up()
    turtle.up()
end

ws.build_wither()