Link to better, GB-specific gfx explanation video

Author: ISSOtm

src/part1/tiles.md

@@ -84,7 +84,7 @@ The first pair of bytes stores the topmost row, the second byte the row below th
 
 Here is a more visual demonstration; note that it's for the SNES, but its 2BPP format is the same as the Game Boy's.
 
-<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/57ibhDU2SAI?start=149" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/txkHN6izK2Y" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
 This encoding may seem a little weird at first, and it can be; it's made to be more convenient for the hardware to decode, keeping the circuitry simple and low-power.
 It even makes a few cool tricks possible, as we will see (much) later!