I liked the marble run bricks that mathgrrl made, but I don't like printing with supports if I can avoid it, so I decided to add a little support to the model and ease the overhangs a little.
I noticed that the long curves 2 brick legs didn't actually match up to pegs on a large plate, so I repositioned them.
I started making steeper and shorter versions of the straight pieces for a little variety. Each model has a consistent entry and exit height as well as consistent lateral position.
I also made an inclined version of the curved track, which tends to lose a lot of speed because it is so long and flat.