up = vector.new(0,1,0)
function greedystep(target)
    --rednet.broadcast(position)
    vec = target-position
    if target == position then
        return false
    end
    if vec.y > 0 then
        if turtle.up() then 
            _G.position = position + up
            return true
        end
    elseif vec.y < 0 then
        if turtle.down() then
            _G.position = position - up
            return true 
        end
    end
    if vec:dot(facing) > 0 then
        if turtle.forward() then
            _G.position = position + facing
            return true
        end
    end
    if vec:dot(facing:cross(up)) > 0 then
        turtle.turnRight()
        _G.facing = facing:cross(up)
        return true   
    else
        turtle.turnLeft()
        _G.facing = - facing:cross(up)
        return true
    end
end
return {greedystep = greedystep}