for the child effect, just follow what the page says and check relevant bits of the location pages (Pyramid Maze and the Ocean Floor) and you should find it.
you pretty much just have to go to the ocean floor and walk to the end of the area, where there should be an egg that will take you to a sectioned off part of the maze with the effect.
for the stretch effect, that's a little bit more complicated. we dont really have a page for the area it involves and I dont think we ever have o.o
I should probably make one knowing that, but I dont really know what to call it, since the 'area' is a cluster of random maps.
all I can do for now is post the first video from google (lol), youll have to improvise cause its old though. http://www.youtube.com/watch?v=B0ZyGrePy5E
just get to the art gallery and use the glasses effect inside the colorful painting, then work your way through the maze - the area with the big circle pattern and the spinning diamonds has changed though, the one you want to interact with is the blue one in the bottom-right corner~
hope this helps you and other people looking for it.