Michael sent this short quiz aimed at measuring your “attractiveness.” Go ahead (if you dare.) Give it a try…

Mike sent this visual illusion. It was devised by Jeremy Hinton some time before 2005. Stare at the +sign. Three effects will appear in order: First, the gap may appear to move clockwise, or a single disk adjacent to the gap may appear to move anticlockwise. This quickly stabilizes to become a gap moving clockwise. Second, the moving gap appears as a green disk. Third, the moving green disk will appear to wipe out the lilac disks, until only the green disk is visible. Here’s a complete explanation along with an interactive version of the illusion.  

I won’t vouch for the validity of the data (there’s an accuracy disclaimer of sorts on the site) but it’s still fun to check out your name and those of  friends…

At first glance, it might not seem so obvious but, as you are about to see, anyone who can subtract can uncover the mystery that makes 6174 so special.

In 1949, mathematician D.R. Kaprekar from Devlali, India, devised the process now known as Kaprekar’s Operation. Here’s how it works:

First, choose a four digit number where the digits are not all the same (that is, not 1111, 2222 …). Next, rearrange the digits to get the largest and smallest numbers these digits can make. Finally, subtract the smallest number from the largest to get a new number and repeat the operation for each new number. … continue reading