The Rice University website says this:
May I submit supplemental materials with my application?
You may augment your application with additional materials if you wish, but we ask you to be selective in what you include. Think about adding to the quality, not the quantity, of your application. You are welcome to submit additional class work, lab work, slides through a Power Point file limited to 10MB, newspaper articles, etc. Please note that supplemental materials must be submitted electronically.
It doesn’t mention additional recommendation letters… If I do submit an additional recommendation, how would I do it electronically? Would my recommender email it directly to Rice admissions or would I have to email it myself?