The block collision puzzle
Total watch time
46m 1s
at 1× speed · exactly 46 minutes, 1 second at 1×
| 1× | 46m 1s |
|---|---|
| 1.25× | 36m 49s |
| 1.5× | 30m 41s |
| 1.75× | 26m 18s |
| 2× | 23m 1s |
Average video15m 20s
Longest26m 7s
Shortest5m 13s
Remaining—
Plan to finish
About 1 day at an hour a day
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Days
At one hour a day, every day, this playlist takes about 1 day. Turn on JavaScript to plan around your week.
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Google Calendar (first session)
The .ics file imports into Google Calendar, Apple Calendar and Outlook — one event per study day listing that day's videos. Subscribing instead keeps the plan in step with the playlist: new videos become new sessions. In Google Calendar use Other calendars → From URL with the copied feed URL.
Videos (3)
46m 1s in total · tick what you've watched
Tick videos you've watched — progress is saved in this browser.
| Watched | ||||
|---|---|---|---|---|
| 1 |
 The most unexpected answer to a counting puzzle
|
5:13 | 2019-01-13 | |
| 2 |
 Why colliding blocks compute pi
|
26:07 | 2025-03-13 | |
| 3 |
 How colliding blocks act like a beam of light...to compute pi.
|
14:41 | 2019-02-03 |
No videos match that filter.
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Markdown
[](https://playlistduration.com/playlist/PLZHQObOWTQDMalCO_AXOC5GWsuY8bOC_Y)HTML
<a href="https://playlistduration.com/playlist/PLZHQObOWTQDMalCO_AXOC5GWsuY8bOC_Y"><img src="https://playlistduration.com/badge/playlist/PLZHQObOWTQDMalCO_AXOC5GWsuY8bOC_Y.svg" alt="Watch time: 46m 1s · 3 videos" width="195" height="20"></a>Add ?speed=1.5 to the image URL for the time at that speed, ?label=Course to change the left text, or ?style=flat-square for square corners.
Want the numbers themselves? GET https://playlistduration.com/api/v1/playlist/PLZHQObOWTQDMalCO_AXOC5GWsuY8bOC_Y returns them as JSON — free, no key. API docs →
Data from the YouTube Data API as of 2026-09-22 (cached). Private or deleted videos are excluded from totals.