I'm sure someone has done this better already, but I just love watching this open and close.
All you need to do is run power into both sides. All the pistons are sticky except for the ones under the concrete powder.
Here it is in action: https://i.imgur.com/9rNSAhR.mp4
I know it isn't particularly impressive, but sometimes you need to make something just because you like it.
"Just a redstone guy"