I am essentially imagining something akin to the DVD screensaver, where it bounces off the edges continuously forever. Is this possible in GEM, and if so, how could I go about doing this?

@fussicks have a look at page 138 of this very useful document...... https://forum.pdpatchrepo.info/topic/12033/multimedia-programming-with-pure-data ... which will show how to do that.
(You might have already downloaded it 5 months ago to solve your previous problem.)

If you then want to go further then see the pmpd library if it is available for your OS or download Pd Extended if not.
David.

I have a lot of this type of stuff on patchstorage with gem files. for basic constant speed vector you make a stair-case type movement up a number in y, and over a number in x. repeatedly and it looks like its travelling diagonally etc.

https://patchstorage.com/explore/?search_query=&tax_platform[]=pd-vanilla&tax_post_tag=&orderby=modified&wpas_id=search_form&wpas_submit=1

this one is sort of low-fi but has the vector stair-case type system.
https://patchstorage.com/pd-gem-foos-ball-like-videogame-for-hid-controller/

this one is pmpd easy vector mass
https://patchstorage.com/hidi-midi-joystick-cannon-game-pd-vanilla-gem-pmpd-hid/

this is a boucing circle
https://patchstorage.com/pmpd-xy-min-max-drawing-system-pd-vaniila-gem-pmpd/

@fussicks this sounds like something I attempted about nine years ago, It may help, but it wasn't very accurate with the collisions
https://forum.pdpatchrepo.info/topic/10993/bounce-a-foray-into-gem