Here's Nintendo's design for a case that turns your phone into a working GameBoy | T3
Game Boy - Wikipedia
Vettoriale Stock A technical drawing and vector illustration of a vintage 1989 Nintendo Gameboy - March 29, 2019 in Bristol, United Kingdom | Adobe Stock
Display & Size comparison between the pocket & an original Gameboy light : r/Gameboy
Nintendo Gameboy Pocket vector drawing
Nintendo Game Boy Dimensions & Drawings | Dimensions.com
Nintendo-Game-Boy-Information-Specs — Gametrog
Nintendo Game Boy Advance (GBA) Dimensions & Drawings | Dimensions.com