Jack is wondering if Leo had heard of LiFi, which uses light to transfer data between the ISP and the computer. This is not the first time we've seen this kind of thing, and there are a number of ISPs that use microwave as well. Microwave and LiFi require direct line of sight. Leo says in theory, this makes sense, as it uses the same type of technology as fiber-optic. But there are issues with this, and this line-of-sight light could be interrupted by weather and other factors.