you simply shuffle all the guests over one room and make room for the next guest. You can repeat this argument for one more guest, two more guests, three more guests, ...infinity more guest... infinity groups of infinite guests, etcetera!
The print shows a grand hotel on a steep angle (with a vanishing point at infinity of course), labelled “Hilbert’s Grand Hotel” below a cameo of Hilbert himself, and the slogan “No vancancy. Check in now!” 🧵2/