This riddle has seen over 140'000 riddlers in the last two years. Level 1 is played by 200 new people every day. The following riddles less of course, because it gets more difficult. The final level was solved by a few people only up to now.
Of course there are different rates. The higher the level, the cheaper the prize for the ad. For more details especially concerning the prizes, please contact me under: info [at] riddle [dot] p4x [dot] ch
I am looking forward to hear from you.