how could that be even possible

if l=2 and w=2 it would output 8 which is not right

It seems to me that all previous years were better, since the point is not in readability, but in the beauty of the code)

Сначала не понял, а потом как понял)

Cool kata

C# Tests are a little bit wrong. Assert.AreEqual() takes the expected value as the first parameter and the actual value as the second.
public static void AreEqual(object expected, object actual);
But in the test cases this is mixed up:
Assert.AreEqual(Kata.CountOfHeads(2, 1, 1), new BigInteger(2));
Assert.AreEqual(Kata.CountOfHeads(5, 10, 3), new BigInteger(92));

fixed

Ruby 3.0 should be enabled, see this to learn how to do it

Please organize the structure of test fixture as following (although it has been mentioned in the attached link, I'm repeated here again)

describe "<This message should describe the categories of test groups inside this block>" do
  it "<A short message describing this test group>" do
    expect(...).to eq(...) #Assertions
    #Or Test.assert_equals(user_response, reference_response)
  end
end

.

C# Translation ready for review.

Fixed

Issue above.

Ruby random tests raise NoMethodError.

This kata should be 7~8kyu if you can understand the question. (¬_¬)ﾉ

Traceback (most recent call last):
File "tests.py", line 1, in
from solution import count_of_heads
File "/workspace/default/solution.py", line 7
def countofheads(init, n, swng):
^
SyntaxError: invalid syntax

Unable to run the sample tests