I remember years ago hearing that a tiny number of repeated perfect shuffles -- riffles -- can restore a playing card deck to its original order? How many? It takes seven shuffles; this is a pretty easy thing to do in Mathematica:

NestList[Riffle[Take[#, 26], Drop[#, 26]] &, Range[52], 8]

Next, I attempted to show graphically each of the intermediate shuffled decks -- far better eye candy than showing a list of 52 numbers. Fortunately Wolfram provides a means of displaying a graphic of a deck with a Resource Function:

ResourceFunction["PlayingCardGraphic"][Riffle[Take[Range[52], 26], Drop[Range[52], 26]], 
 CardSpreadAngle -> 0, ImageSize -> 1000]

One thing I learned during this exploration was how to apply an option of a Graphic to a ResorceFunction that doesn't provide that option. The "ImageSize->1000" is passed straight to the Graphic constructor. Without that option, the 52 cards get crammed together into an unreadable scrawl. :(. I then tried to apply the card-display function repeatedly with a NestList:

NestList[ResourceFunction["PlayingCardGraphic"][Riffle[Take[#, 26], Drop[#, 26]], CardSpreadAngle -> 0, ImageSize -> 1000] &, Range[52], 1]

This doesn't work. I want to pass the numeric list through the iterations of NestList, but I want to display the Graphic on each iteration. This strikes me as something that should be easy, but I'm missing a bit of understanding to do it. I've attached my Notebook to the end of this message. Please assist. Thanks.

I'm seeing a wonky behavior in the framework. If I go back to Quiz 4 in the framework, my score is there. However, the correct answers are erased. Reloading the webpage doesn't change this. Closing all webpages and flushing every wolfram-cookie in my browser doesn't change this. Rebooting my computer (M1 iMac) doesn't change this.

I'm running Sarari on the iMac. If I open to Quiz 4 in Chrome, the answers are filled in. If I open with DuckDuckGo, the answers are filled in. If I run Safari on a different computer (M1 MacBook Pro), I'm able to see my answers to Quiz 4 filled in. Strange! Is the framework doing anything different for Quiz 4?

It appears to me that the first question in Quiz 5 scores incorrectly.

Hello Rory,

This study group is entertaining and covers material not explored in other study groups. One favorite is keyboard shortcuts: they are a great timesaver that every user needs to know.

I found two problems :

• The link in yesterday's email for the study group materials is broken.
• Quiz 5, problem 3: the correct answer is marked as wrong.

"See" you at 11:00!

Hi, Alex. This link was in the Chat part of yesterday's webinar.

I think that's what is meant by "framework". There you can watch the videos and recordings, read materials and take quizzes.

Hope this helps,

Mark

Some tips I remembered tonight:

One cool detail of the Wolfram Language & System Documentation Center is searching on a shortcut. If you put a shortcut into the search box (e.g., //, #, &, /@, etc.) you will go to a page documenting both the shortcut and non-shortcut forms of the shortcut.

Doing the non-shortcut form -- invoking the function with no shortcuts -- is essential to mastering the shortcut. I like saying the full name of a shortcut to myself whenever using one.

The documentation can be brought up as a window in the Mathematica App, or it can be found on the web at https://reference.wolfram.com/language/ . At different times, one way or the other will be better for consulting the docs.

When using the framework, there are times when it's easier to have one of the framework windows in its own tab. On the Mac, you can right-click in a window and select "Open Frame in New Tab". I'm guessing there is a similar way to do this on Windows and Linux.

NotebookDelete[Cells[]] will erase everything in the scratch notebook.

Phil, I agree that Quiz 1, Question 5 is a problem. All of the answers are built-in symbols, not unassigned variables. One way to check this hypothesis is to try to assign them values:

Black = 1

If Black is an unassigned variable, then the assignment will work, otherwise you'll get an error message that says "Symbol Black is Protected".

Probably one of the answers is supposed to be lowercase.

Hi there! Ah, I agree on Quiz 1, Question 5. It's much more misleading than we intended. The question is actually referring to what color the notebook shows an undefined variable (ie with syntax highlighting). I'll get that question edited for clarity.

Thanks for the feedback! I'll have a look at Quiz 2 question 4.

Dear Rory, The issue with problem 4 in quiz 2 still persists as checked a few minutes ago.

Attachments:

20240509 Problem 2.4.nb