The second set shows a rather static design, although it is a bit more than just static as the squares run over the edges of the white block:
The other four designs are done with pencil lines. The first one is a serene design, just 2 straight lines at a different size away from the edges of the white block. The second one plays a bit with this idea. The vertical lines are straight and four of them are at exact the same distance. The two diagonal lines make the design a bit more playful. They run exactly parallel to each other.
The third one is a continuation of the same idea. Diagonal lines running parallel to each other. If I combine the second with the third one, my preference goes out to the second one. The combination of the straight lines with the diagonal ones makes it more interesting than only parallel diagonal lines.
The final sample is a combination of diagonal lines. The block on its own is okay, but if you repeat this design and change the position of some of the blocks it becomes much more interesting.