Coord Vector Functions

    -- pastebin get PE0k7NQY CVF

    CVF = {}

    function CVF.add(pos, delta)
        local dy = delta.y
        if not delta.y then dy = 0 end
        if pos.y then dy = dy + pos.y end
        return {x = pos.x + delta.x, y = dy, z = pos.z + delta.z}
    end

    function CVF.sub(pos, delta)
        local dy = 0
        if delta.y then dy = -delta.y end
        if pos.y then dy = pos.y + dy end
        return {x = pos.x - delta.x, y = dy, z = pos.z - delta.z}
    end

    function CVF.mult(s, vec)
        local newVec = {}
        for k, v in pairs(vec) do
            newVec[k] = s * v
        end
        return newVec
    end

    function CVF.equalCoords(coord1, coord2)
        return coord1.x == coord2.x and coord1.y == coord2.y and coord1.z == coord2.z
    end

    function CVF.getRightDir(orientation)
        return {x = -orientation.z, z = orientation.x}
    end

    function CVF.getLeftDir(orientation)
        return {x = orientation.z, z = -orientation.x}
    end

    function CVF.isXDir(dir)
        if dir.x ~= 0 then return true end
        return false
    end

    function CVF.getTurnDirection(from, to)
        local function vectorsEqual(a, b)
            return a.x == b.x and a.z == b.z
        end

        if vectorsEqual(from, to) then return nil end
        local left  = {x = from.z, z = -from.x}
        local right = {x = -from.z, z = from.x}
        local back  = {x = -from.x, z = -from.z}
        if vectorsEqual(to, left) then
            return "left"
        elseif vectorsEqual(to, right) then
            return "right"
        elseif vectorsEqual(to, back) then
            return "around"
        else
            error("Invalid target direction")
        end
    end

    return CVF