That'll be interesting if Art has figured it out.
And we now seem to have confirmation that Zack-Grain's form is based on the headmaster of Hero High:
http://dhscomix.com/comics/comic.php?v=47&p=2
Art may have pieced it together that his form here (http://dhscomix.com/pcomics/pcomic.php?p=88) must be incredibly similar to his true appearance. Arthur has seen Grain's base form, albeit palette swapped, at least twice, other time here: (http://dhscomix.com/pcomics/pcomic.php?p=96)