Our "pink" tower that the 3yo did last week. It is a set of wood nesting blocks, different images on each side, but the same arrangement of images for each block. I was going to repaint them at one point, but then I noticed how older kids paid attention to the images--it became more of a challenge--and the younger they were, they tended not to. It's kind of fun to see that "oh!" moment kick in when they realize they can match up the images. As you can see, she hasn't hit the "oh!" moment. ;)
This is from an experiment from dd's French workbook (it covers all subjects, but for French-speaking students). Green water, vegetable oil on top, then you sprinkle a bunch of salt. The "bubble" you see in the middle was the result of salt, stuck in oil, had dropped down to the bottom and is now going back up.
I decided yesterday that given how she'd done the cylinder blocks the previous week, I was going to present two at a time. So I pulled them out, did not get a chance to show her before she sat down with them. I decided to just kind of observe how she would do. It was too hard for her, BUT she decided to do some knobless cylinder towers. :) The first one she did was actually more how it should have been; here, she tried to mix the two sets of cylinders. She watched me look at the cylinders to decide where to put them back and was able to do some of them. It's possible I picked the wrong 2 blocks to start with.