Here’s a fun puzzle I heard from Christopher D. Long (npub1k8l…6pkl)
Pick two points uniformly at random in a square. What is the probability that the line that contains both points intersects two opposite edges of the square, rather than two adjacent edges?
Greg Egan
npub12c…gd38p
2025-08-22 13:12:02 UTC
Author Public Key
npub12cuzzqzv8e8y7na77a9zv47mx2v6pec60qs5h7takzmv5p0mw0fsmgd38pSeen on
wss://relay.momostr.pinkPublished at
2025-08-22 13:12:02 UTCEvent JSON
{
"id": "f5c1e9b9d05ab10b2fd922608f80e08cd8241bcf689af2cf6f58255136e998a0",
"pubkey": "563821004c3e4e4f4fbef74a2657db3299a0e71a78214bf97db0b6ca05fb73d3",
"created_at": 1755868322,
"kind": 1,
"tags": [
[
"proxy",
"https://mathstodon.xyz/@gregeganSF/115072586396939751",
"web"
],
[
"p",
"b1fff3be99512e564658ba139387e031dacf8c05405de2953d97904eb92b156e"
],
[
"proxy",
"https://mathstodon.xyz/users/gregeganSF/statuses/115072586396939751",
"activitypub"
],
[
"L",
"pink.momostr"
],
[
"l",
"pink.momostr.activitypub:https://mathstodon.xyz/users/gregeganSF/statuses/115072586396939751",
"pink.momostr"
],
[
"-"
]
],
"content": "Here’s a fun puzzle I heard from nostr:npub1k8ll805e2yh9v3jchgfe8plqx8dvlrq9gpw799faj7gyawftz4hqj86pkl \n\nPick two points uniformly at random in a square. What is the probability that the line that contains both points intersects two opposite edges of the square, rather than two adjacent edges?",
"sig": "9b31e1c805d3bb69cff17b9f5a95940f227214020042b6545c6099fb3b8ffa344534ba5026deddab0ae1b1be582112ef82a258d3b585b29d4dce2c4271d4b5fd"
}