Dedicated to a colleague who teachers students to think! (and they thought they were just learning physics in his class).
The wallpaper version is available at the preceding link.
Today's Gratitude Item: Finally tracking down the zog game which I will use to help my students get the hang of linear equations. I remember using it last year but managed to lose track of the link. It took a while to find it again (mainly because I could not remember what it is called).