Lernkarten for Rubik's Cube - Fridrich Method

This project provides Lernkarten (German for learning cards) for memorizing the algorithms needed to solve a Rubik's Cube using the Fridrich Method (CFOP). Two kinds of cards are provided:

• Anki flashcards for spaced repetition learning
• physical printable cards for offline study

The icons will be generated from provided algorithms, so that the icons are guaranteed to match the algorithms exactly.

All SVGs, CSVs and PDFs are easily regenerable using the provided scripts. However, they are added here so that users can directly use them without getting into technical details.

Structure of the Repository

The repository is structured into folders for each type of algorithm.

Algorithm Set	Example	Description
2-look-oll		Lernkarten for the eight 2-Look OLL algorithms (omitting edge orientation)
oll		Lernkarten for the 57 OLL (Orientation of the Last Layer) algorithms
pll		Lernkarten for the 21 PLL (Permutation of the Last Layer) algorithms including rotation arrows. Note: The icons show the cube you get by applying the algorithm repeatedly with the blue face in front.
big-cube		Lernkarten for some big cube algorithms (4x4 and larger)

Additionally, there is the lernkarten_scripts folder containing a Python program for regeneration of the icons, CSVs and PDFs.

Using the Lernkarten

Anki Flashcards

Each flashcard folder contains icons and a file ankiCardSet.csv. In order to import them into Anki, follow these steps:

• copy the SVG files into Anki's media collection folder (see here for how to find it)
• import the ankiCardSet.csv file using Anki's import function

Now you should see the cards in your Anki collection.

Physical Printable Cards

The printable cards are provided as PDF files. They are designed to be printed two-sided (short edge tumble). Then the algorithms will be on the back of the corresponding icons.

The PDFs are designed to be cuttable in batches, allowing for more convenient preparation.

How to Regenerate the Lernkarten

Everything required to regenerate the Lernkarten is provided by the Python program in lernkarten_scripts/. In order to run it, one needs to have uv and Python 3 installed. One ad-hoc way to install uv is to run

pipx install uv

, but make sure to check the official installation instructions and your platform's best practices. For instance, on Arch Linux, uv can be installed via pacman.

After that, the script can be executed by running

uv run generate-algorithm-cards --help

, which will show the available options.

How to regenerate Anki flashcards

In order to regenerate the Anki flashcards for algorithm set OLL, run the following command from the project's root folder:

uv run generate-algorithm-cards --algorithm-set oll oll-output-dir

This will regenerate

• the SVG icons using visualcube.api.cubing.net
• the ankiCardSet.csv file for Anki import
• a Makefile and Lernkarten.tex file for generating printable cards

Regarding Anki, this is all that is needed.

How to regenerate physical printable cards

In order to regenerate the printable cards, the $\LaTeX$ file needs to be compiled to a PDF file. Ideally, this can be done using the Makefile:

# Regenerate printable Lernkarten for OLL. Replace "oll" with any other
# algorithm set folder name as needed.
make -C oll-output-dir

Unfortunately, the Makefile is not portable across different systems. If it cannot be used, the following steps need to be done manually:

• All SVG files need to be converted to PDF files with the same name. For instance, the file pll/Ja.svg needs to be converted to pll/Ja.pdf.
• The Lernkarten.tex file needs to be compiled using lualatex. The time-honoured pdflatex will not work.

How to change algorithms

In order to change the algorithms used for generating the Lernkarten, the file lernkarten_scripts/algorithms.py needs to be edited. There, the algorithms are defined in Python lists. Since the icons are generated from the algorithms, changing the algorithms and regenerating the Lernkarten will automatically update the icons as well. This works very well for OLL and 2-Look OLL.

Attention: The arrows and setup rotations for PLL algorithms are not generated automatically. They need to be adjusted manually too. They are defined right next to the algorithm.

A Note on Deck Usage

When using the Lernkarten in Anki, it is recommended to set up a big deck containing all the cards. This allows for better spaced repetition learning across all algorithm sets. This is in line with the recommendations of Anki itself.

The author started with four decks (OLL, PLL, F2L and Big Cubes) only to be overburdened by tracking progress on multiple decks. Switching to a single deck hands over the bookkeeping to Anki. In particular, limits for new cards are consolidated across all algorithm sets. Without that, after learning some new cards for one deck Anki would have you learn new cards for another deck, which is counterproductive and overburdening.

Instead of multi-deck usage, the tags can be used to create filtered decks for focused study sessions on a particular algorithm set. With that, one can still learn some cards first, e.g. 2-Look OLL or PLL, before moving on to the full set.

Acknowledgements

I want to thank Andy Klise of https://www.kungfoomanchu.com/ for providing excellent guides. Without these I wouldn't have started learning the Fridrich Method in the first place.

Another great source of algorithms was Feliks Zemdegs project https://www.cubeskills.com/. The provided algorithms there allowed me to fine tune the algorithms used in this project.

While there are some cube visualization tools available online, none of them match the brilliance of visualcube.api.cubing.net. It is feature-rich, scriptable and produces impressive icons.

Last but not least I want to thank the anonymous contributor of Anki cubing flashcards found here. They were a great starting point for creating my own Anki cards.