When you pick them up in time-out, if you want to do a little ritual about no hitting, no hurting, no messing, that's fine, but then you get them back into a positive activity. You take them over to the toys and the best way to do it is just to start narrating. Oh, the blocks are on the floor. And then, if they come out of time-out into dead space, they're going to go right back to the negative behavior because they won't have anything else. If you can get them into something positive, then they're going to stick with it.
Toddlers use a lot of negative behavior.
They do a lot of misbehavior just to see what you're going to do next and just to learn what your moves are. It's how they learn. Don't be discouraged. Expect them to do it. Anticipate what your next move is going to be if they do it.