Bekhorot 17: three things to remember

Wool from an animal that resembles another species is invalid for ritual fringes and exempt from shaatnez and tzaraat garment uncleanness.
When twin male lambs emerge simultaneously, Rabbi Tarfon awards the priest the fatter lamb, while Rabbi Akiva gives the leaner one.
The Sages rule natural births cannot coincide simultaneously, debating whether human measurements can ever achieve exact equality.