When my nephew was little, I used to tease him that he didn't know the difference between bananas and apples. "Uncle Tom, a banana is yellow!" So I bought a Golden Delicious apple. "No, when you peel a banana, it's white inside!" I sliced the apple open, and it was indeed, white inside. "When you eat it, it has a curved shape." So I sliced the apple lengthwise and removed the seeds. It had a crescent moon shape, and I put it on a plate for him. "Uncle Tom, it's not a banana, it's still an apple!" His four year old brain couldn't describe to me what an apple was, or how it was different from a banana, but somehow he knew that there *was* a difference. That's it. That's the tweet.