http://www.notessimo.net/topic/7292-13-tuplet-challenge-in-v2/

The challenge is to cover these 2 measures with both the 13-tuplets and the triplets perfect in tempo 240:

It obviously wouldn’t be hard if there weren’t those annoying triplets in the bass.

I haven’t yet found a way to do it, but here are some attempts:
There are 5 different versions:

• x1.5 (triplets perfect in duration 8, 13-tuplets in durations 4 and 8 for both measures)
• x2.25 (triplets perfect in 12, 13-tuplets in 8 and 12 for both measures)
• x3 (triplets perfect in 16, 13-tuplets in 8 and 12 for the first measure; 12 and 16 for the second.)
• x3.25 (13-tuplets perfect in 12 for 1st; 16 for 2nd, triplets in 16 and 20)
• x3.75 (triplets perfect in 20, 13-tuplets in 12 and 16; 16 and 20.)

So ye, the 4th version was by far the closest with its perfect 13-tuplets and almost perfect triplets. Any faster speed would make the tempo over 999 so there’s no point in that and any slower tempo would make both the 13-tuplets and triplets imperfect.

Feel free to try the challenge yourself. Let me know if you find a solution.