Project · Ping-Pong with Threads

Two concurrent workers take turns printing 'ping' and 'pong' — 10 times each, strictly alternating, never out of order, without busy-waiting or sleep tricks. Pick any language from the tabs (Go, Python, Rust, or Node.js) and ship a runnable file plus a README explaining how the ordering is enforced.

• A single source file (main.go / main.py / main.rs / main.js) that runs with one command from the README.
• Output that is exactly 20 lines: ping pong ping pong … always alternating, starting with ping.
• A short README section called 'How ordering is enforced' — one paragraph explaining the synchronization primitive you used (channel, mutex+cond, semaphore, etc.) and why it cannot deadlock.
• At least one deliberately-wrong variant (commented out, or in a `broken/` folder) that demonstrates the race you would have had without the primitive — plus a one-line note on what you observed.

• Output is strictly alternating across 1,000 runs — verify with a tiny shell loop.
• No `sleep`, no busy-wait on a shared counter, no `Thread.yield` as the mechanism.
• Synchronization is explained in the README in terms a junior could follow.
• The broken variant actually exhibits the race (non-deterministic output) — not a trick.