How to run the poll
One person creates the poll, picks two to seven candidate dates and an hour range, and shares the link. Everyone else opens it, types a name and paints the times they are free. The grid darkens where more people are available, so the meeting slot usually picks itself. There are no accounts and no invites to accept: the link is the poll.
The grid is stored as real moments in time rather than wall clock hours. The creator picks 09:00 to 18:00 in their own zone, and someone in another country sees those exact moments in theirs, which may land at unusual hours or spill onto a different local day. That is the honest answer, and it is the point: it stops the classic mistake of agreeing on two o'clock without agreeing on whose two o'clock.
Dates can be changed until a second person answers, after which the grid is locked so that nobody's answer silently moves. Votes stay live for about thirty days after the last activity and are then deleted.