Why is the GameCube a cube?

The Nintendo GameCube made its debut on September 14th, 2001. The world has never been the same.
Sources:
Patent 1: GameCube Patent of Internal Hardware
patents.google.com/patent/US7...
Patent 2: GameCube Patent of External Hardware
patents.google.com/patent/US6...
Game Informer 2006 Interview:
web.archive.org/web/201401201...
CNN 2003 Keighley article: Gaming Consoles as multimedia
web.archive.org/web/201401200...
Nintendo Europe 2002 interviews: Miyamoto Gamecube Cube Interview
web.archive.org/web/201401201...
GameCube design 2000 article: Yoshiko Hara
web.archive.org/web/201401192...
Yamauchi: Yamauchi 2003 GameCube interview
web.archive.org/web/201401201...
Bloomberg Kunii: Analysis in 2003
web.archive.org/web/201401032...
2001 GameCube Commercial:
• Nintendo Gamecube Comm...
2001 E3 footage:
• Nintendo GameCube E3 2001
2001 Ashida:
spong.com/article/2195/A-day-...
Mango vs Armada (HMW):
• Mango(Puff) vs Armada(...
Mew2King vs Leffen EVO 2017:
• EVO 2017 - Mew2King (M...
Iwata Asks Hardware:
iwataasks.nintendo.com/interv...
Iwata Asks Design:
iwataasks.nintendo.com/interv...
GameCube Elite Ashida Kenichiro: Kenichiro Old Design Interview
web.archive.org/web/201401201...
2000 E3 Yamauchi: Yamauchi Interview
web.archive.org/web/201604021...
2000 Wit Capital Yamauchi:
www.gamespot.com/articles/yam...
I like this summary on the history of the GameCube: GameCube article (A Dolphin's Tale)
gwern.net/doc/technology/2014...

[@user-xv9jc7vu4l]

It's clear you make great work! I'm happy to be an early viewer of your content before you (inevitably) become a big. Congratulations in advance!

[@blu3_chao555]

Surprised this hasn't got more views, it was the first thing that came up while looking for an answer