Someone did it for me $20$ Years ago. It was using $12$ Numbers in this example $1$ to $12$ and there were $42$ sets of $6$ numbers.
In that sample each of the $12$ numbers ONLY appears $21$ times, so this tells me it is a balanced result.
It covered the Majority of combinations and at least every combination of $4$ was presented.
I was to "believe" that in the example EG line $1-1,2,3,4,5,6$ that this was only time $1,2,3,4$ existed together.
But so does every other set of four combinations SO in LINE $1$ Many Combinations Exist $(1,2,3,5 / 1,2,3,6 / 2,3,4,5 / 2,3,4,6 ...etc)$ and I call this a set of 4, but because we are extracting 6 numbers and within those $6$ we can cover the set of $4$ combinations. Where the normal calculation of having $12$ numbers and wanting every combination of $4$ is $495 $ Combinations. But here we are using a string of $6$ numbers but ONLY looking at the sets of $4$ in it. I am not sure how they got this result? But I have a problem where I now have to have $7$ numbers...it will take more than $42$ sets
$$ 1-1,2,3,4,5,6,\\ 2-1,2,3,7,8,9,\\ 3-1,2,3,10,11,12,\\ 4-1,2,4,7,8,10,\\ 5-1,2,4,9,11,12,\\ 6-1,2,5,7,8,11,\\ 7-1,2,5,9,10,12,\\ 8-1,2,6,7,8,12,\\ 9-1,2,6,9,10,11,\\ 10-1,3,4,7,9,10,\\ 11-1,3,4,8,11,12,\\ 12-1,3,5,7,9,11,\\ 13-1,3,5,8,10,12,\\ 14-1,3,6,7,9,12,\\ 15-1,3,6,8,10,11,\\ 16-1,4,5,7,10,11,\\ 17-1,4,5,8,9,12,\\ 18-1,4,6,7,10,12,\\ 19-1,4,6,8,9,11,\\ 20-1,5,6,7,11,12,\\ 21-1,5,6,8,9,10,\\ 22-2,3,4,8,9,10,\\ 23-2,3,4,7,11,12,\\ 24-2,3,5,8,9,11,\\ 25-2,3,5,7,10,12,\\ 26-2,3,6,8,9,12,\\ 27-2,3,6,7,10,11,\\ 28-2,4,5,8,10,11,\\ 29-2,4,5,7,9,12,\\ 30-2,4,6,8,10,12,\\ 31-2,4,6,7,9,11,\\ 32-2,5,6,8,11,12,\\ 33-2,5,6,7,9,10,\\ 34-3,4,5,9,10,11,\\ 35-3,4,5,7,8,12,\\ 36-3,4,6,9,10,12,\\ 37-3,4,6,7,8,11,\\ 38-3,5,6,9,11,12,\\ 39-3,5,6,7,8,10,\\ 40-4,5,6,10,11,12,\\ 41-4,5,6,7,8,9,\\ 42-7,8,9,10,11,12,\\ $$
