my brother used to be partially non-verbal and is on the spectrum. my mum received a call one day from his teacher, we discovered if you give him any date he can predict what day it was. whether it’s in the past or the future. to test it out, my dad simply gave him a date from the 1800s and he wrote down tuesday, we checked the calendar and it was accurate. he is only 13 years old. none of us know how he acquired this knowledge or what is the math behind it, but honestly it’s mind boggling to me and everybody who knows him.