Let's talk about this puzzle game. The two images show a very easy level. Inside each grid are one or more hidden diamonds. These diamonds are located on the small circles. At the start of each level, you are presented with a blank grid. Tap a square outside the perimeter and that ball will shoot through the grid. If you look at the second image, it's clear that one of the diamonds belongs in the upper left circle.
The grid sizes get bigger, and with that, the difficulty. I polished off the 20 easy levels quickly. The medium puzzles are quite tough! On those levels, there are 5 hidden diamonds on a 5x5 board. I have not solved the first medium level - after 7 or 8 attempts!
Predikt - Hidden Object Puzzle Game is very similar to an old board game called Black Box from 1977. For more info on that, go to Board Game Geek. There is always one for sale on ebay for about $5-$10.