optical confusions

When our classroom weather girl delivered the daily forecast this morning, the room was abuzz with excitement.  Could it be?  Another possible snow day?  I managed to regain their focus long enough to impart some wisdom about character development in literature (don't be too impressed...it definitely involved a robust discussion about Spongebob's finest attributes).  But just when the bell was about to ring, one student of mine, who is quite a character himself, could hold his excitement in no longer.  As he swooped his backpack up off the floor and slung it over his shoulder, he called out, "Hopefully we'll have another snow day tomorrow!  Keep your eyes crossed!"