First sight word

Outside the other day Nate was pushing the grass seeder and Z looks down at it and says, "Hey Dad, why does that say zoo on it?".  Nate looks down and sees "Scotts AccuGreen 2000", but the 2 kind of looks like a Z.  Totally out of nowhere. 
Later on that night, Nate writes ZOO on a paper and asks Z what it says, and he goes, "Oh, ZOO!", then proceeded to get up and write down zoo without looking at Nate's copy.  No idea where he learned that Z-O-O is zoo, but he did.  His first sight word besides his name.  Good job, big boy!