Xactly

One is expected to know it from part 1 of this kata and furthermore the description says:

The moves of the selection cursor are the same as before: rotate horizontally but stop vertically.

he used this one:
http://www.mathopenref.com/coordtrianglearea.html

I've created some random tests for the Python version, they use all the 4 instructions and never get to infinite loops.

[Python] I think 1000 random tests were too many, so I've reduced them to 300.

Interesting idea and fun to solve. The short but clear description is definitely a plus.
I believe you can make it evolve into a series of increasingly difficult katas, adding new instructions for example.
You should consider opening it for translations.

I've modified the description and added some random tests.
More in general, this is a "template" I use for Java tests with random numbers:

// random numbers tests
import java.util.*;
@Test
public void testRandomValues() {
  Random rand = new Random();
  int min_value = 1;
  int max_value = 1000;
  for(int i=0;i<80;i++){
    int v1 = rand.nextInt(max_value - min_value) + min_value;
    System.out.println("random value: " + v1);
    assertEquals(authorSolution(v1), userSolution(v1));
  }
}

Although I don't find a kata in Javascript and Python about reversing strings (nor putting it between "#") original after more than 4 years of Codewars' life (and I want to highlight Javascript and Python, cause probably it would be more challenging to reverse a string in some other languages without finding it on StackOverflow), I've added the random tests for Javascript and closed issues about (no more) missing random test cases for Python. Cheers.

[solved]

[solved]

.

.

I don't know if anyone noticed anything odd in the description picture...

done.

done.