Monday Morning Workout...

Again, regulars here know I'm fond of self-reference puzzles, and "MathMama" recently cited a 'self-referential number square' from Jack Webster:

http://mathmamawrites.blogspot.com/2013/08/self-referential-puzzle-by-jack-webster.html

(...it ain't easy!)
Here's an updated, 'cleaner' version of the same puzzle from Jack (…with the solution available):

http://jaxwebster.wordpress.com/2012/06/20/self-referential-number-square-1-updated/

and MathMama also links to this Webster page with a few more in the same genre, if your brain is ready for additional punishment:

https://sites.google.com/site/jlnwebster/mathematics/puzzles-1