Attached to this post, along with the main project page, is the draw_object_along_shape function and an updated demo.

Demo project updates: 

• Removed rooms 2.1, 2.2, 2.3
  • They are now just room2 and you are able to add any number of shapes instead of capping out at 3.
• Added the option to save and reload shapes in room 2
  • This saves the shapes to both a json file and a text file.
  • The text file is saved in a way for you to be able to copy/paste the shape as a struct in GML.
  • Added a few supporting functions to randomize the shape structs for use in draw_sprite_along_shape_ext().
• Function addition: draw_object_along_shape()
  • Allows you to use objects as points(corners) of the shape and objects to make up the line of the shape.
  • Added room 4 which showcases this function.
  • Added an example of toggling visibility of the objects in the shape instead of destroying them.
    • Allows the object to keep it's shape instead of auto resizing like room 3.
• Added 2 more shape sprites for a bit more variety:
  • Heart
  • Star
• A short showcase video of the demo added to the itch.io page.

Unless anyone or I come up with some new features, I believe this should be the last update for a while. If anyone has any requests or needs help; reach out and ask! :)