Phone/tablet charging rack

This is a rack for holding phones, tablets, and similar devices for charging. It's designed to have an [Anker USB charger](https://www.amazon.com/Anker-Charger-PowerPort-Multi-Port-Samsung/dp/B00VH8ZW02) popped into it; it will hold the charger in place so that you can readily plug USB cables into it.

I *think* that's the particular Anker model that this is designed for. Measure yours and adjust dimensions as required.

Full disclosure: in preparation for publication, I improved this a bit. I haven't actually printed the improved version because I don't need another one. It *looks* OK...