They are super handy to use so I'm going to show how I make these.
Oops, I used a bit too much here but I'll poor it over
into another tray as I'm going to make lots of plaster plaques!
Since I actually use the smooth side, I thought I could use the bottom too to create some textures... You can see what I did with the textures here.
It's freaking smooth - love it!