A number of letters in our alphabet contain symmetries. More specifically, several letters can be reflected across a horiztal or a vertical line going thorugh their center. The screen below will allow you try selecting the ones with these two symmetry.
To get you started, look at the following animation of the letter A. Note that letter does indeed contain a reflection across a vertical line. The entire image is recreated by simply flipping half of it over a central line.
Now it is your turn. First try to select all those with these symmtries and then you can check if you got them all by selecting the others. Note that there are two rows of circles - one for each type of line to reflect across.