I taught my cat to do it for treats. For weeks after, he would walk around the house high-fiving the furniture and look offended when a treat didn't fall from the sky.
In order to use a bit of Windows only software for controlling my CNC machine, I have to use a Wine patch that is only available in source form. That means building Wine from source if I want to use my CNC
Also true, but only if you can locate every single homeless person in the country. Though I'm not sure I would consider "legal shelter" a high enough bar to consider homelessness solved for that person, even for a short duration. At minimum, I think it would require them to have control of some sort of "permanent" residence, such as a month to month rental. Not simply space at a shelter.
They are both Cornish Rex. Here is a better angle on him.