Rapid Intelligence by Jay Schwausch

“You have in your hands what I believe to be the best version of the “day of the week” routine. I have heard and seen numerous versions of this tossed about here and there. However, even the ones I thought had hit on the solution ended up having flaws revealed when put to the test. In addition to compensating me for the errors that others failed to do, I also made the task a little easier by adding a couple aides to the performer hidden (?) within the design of the souvineer card. My method covers any date from 1900 to 2099! And with a little common sense and thinking you can expand it even beyond those dates!”