After dinner
The earth is round.
After the dinner with Professor Liu and other Postdoc/PhD students in Seattle, Professor Liu wanted to visit the Space Needle. He asked a PhD student to lead our way. We walked about 100 feet before that PhD student found we were going the opposite way. Then Professor Liu asked:
"Can we get there if we keep going that direction?" he asked, pointing in the opposite direction.
"Well, the earth is round, so..." I said.