I'm more an "ideas" person
I "invented" this in grade 2 or 3:
New Invention Roller Coaster
Can take you to school, outerspace, and under water. 10 people can fit in one.
(Really, all the places a kid would ever need to go!)
Even then I knew that numbers 10 and higher should be represented numerically, and that numbers under 10 should be written out. (Remarkable!)
I clearly remember deciding to make the whole transitway out of wood. (In the center of the drawing you can see I actually drew one panel of boards held in place by nails, then gave up and just coloured the whole thing brown to convey the idea of wood.) I guess my understanding of structural and material integrity was a bit underdeveloped. Because otherwise I suppose I might have thought about using something a little stronger than wood to go into outerspace and under water.
Note also that I deliberately set a few of the roller coaster cars on a collision course and their drivers look worried, and that the driver splashing into the water is screaming. I think I imagined collision course cars would just hop over each other somehow, but then, as evidenced in my materials selection, I really wasn't thinking that clearly about the details. I probably just set it up like that to make my friends laugh.
Also dig the Hello Kitty stamps. And that I was doing some arcane name-numerology-love-compatibility calculations with my friend Joanne's name and those of some of her suitors/love-interests.
Joanne ended up being a competitive biathlete. I wonder if things ever worked out with Kevin or Jason and if they liked her lycra outfits and rifle.