[everdev]

I'm guessing you locate your month on the top, then locate the day of the month and it tells you what day of the week it is.

It's an interesting design exercise, but I can't imagine people using this day to day.

[benatkin]

My thought was "Your calendar is bad and you should feel bad." It's a reference and I don't actually mean that, except as a reaction to seeing it after clicking the title on HN which had me expecting something I might want to use.