Grandpa explains it all

Joy and I went to visit grandpa yesterday and today.
he got so excited to see joy that he decided to give us both grandpa-lectures.

in my lecture, he explained einstein's theory regarding humans:
"...energy=mass, they are equal and not, they are the same and different. this is like man and woman, the particle and anti-particle...they are not the same but they need each other to complete the equation..."

it's the first time grandpa almost made sense to me.