Kerflux is a very unique puzzle app game.  As far as we know, it's the only puzzle that utilizes waves.
The object is to manipulate the waves on the left to get the right-most wave to line up against its shadow perfectly. The early levels require the solver to manipulate just two waves. Then 3 waves. Finally, 4 waves.
Many of the levels take just a few seconds to solve because once you get the knack, they're all pretty much the same.  There are 100 levels and I solved them all yesterday in about 2 hours. No level took more than 5 minutes.
After level 13, you get the above image, which I positively love. I paid $.99. I would like to see other puzzle apps have something similar. Maybe at the very end.
More thoughts
1. Apparently, if you're stuck, the background music will somehow give guidance.  Loyal Blog Followers know that I always turn off all music and sound effects for all puzzle apps because they're often annoying and use up valuable battery life.

2. As I mentioned, all the levels are pretty much the same. I can't say: Level 83 was particularly ingenious. Nor can I say that I had an 'Aha' moment.

3. Still, I did spend the time to complete all the levels - on the same day no less. I did like it.
http://kerflux.com/
https://itunes.apple.com/app/kerflux/id1127933116"mt=8

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