Yaay, you got the reference correct. Oh how I love watching people playing “Keep Talking and Nobody Explode” and “Bombanana” where they restrict communication. So I imagine them but only communicating with drawing. Because the unique properties of window is drawing on condensed window and the person on another side will see it flipped horizontally. Therefore I make the rune similar but flipped.
A bit struggling on how to communicate it properly without giving away too much.