Eric agreed to write the “simple equations” that come from Lorentz’s Transformations of Relativity. Eric wrote out the equations and then we wandered around Iowa State’s campus briefly before going to get some grub.

Sometime after lunch, Eric realized that he had written one of the equations incorrectly. This tortured him.

So he went into Photoshop and corrected the error and sent me this email:

Would you allow the alteration I applied to this photo? Chances are you can’t find the change quickly (or perhaps at all). There’s an integrity to undoctored photos, but there’s also an integrity of mathematical truth, which I violated and have thus remedied.

Here is the image with the equation corrected:

I have no doubt that the initial error might have been caused by the interruption of the security guard that came up to ask us what we were doing. When we explained, he noted that “this” was the “best part of his day”.