The most impressive boundary’s not a wall. It’s not a manufactured thing at all. Moving towards it won’t reduce the gap and nothing marks its presence on a map.
Nipples or teats. Cows have four of them, dogs usually have eight and a human (assuming that’s who’s reading this) has two. Cows milk standing up, dogs often lie down and women usually sit when breastfeeding.
Joe and Andrea want to copy three 60-minute cassette tapes. They have a 2-cassette recorder to copy the tapes, allowing them to copy two tapes at a time. Each side takes 30 minutes to be copied, so two tapes can be copied in an hour and the third will take another hour. Andrea bets Joe she can copy all three tapes in 90 minutes. Does she win the bet?
In the first 30 minutes Andrea copies the A sides of tape 1 and 2. In the second 30 minutes, she copies tape 1 side B and tape 3 side A (finishing Tape 1). In the last 30 minutes, she copies tape 2 side B and tape 3 side B.