Your 30 week old baby is now starting to understand dimensional galaxy. You may see his/her try to sort toys and blocks by size. She/he is probably also fascinated with his/her reflection and games like peek-a-boo, where people or his/her favorite toys withdraw and return.
Your baby can see evidence of this not only in his/her crawling and movement, but also when you attempt to do something the baby is opposed to, like putting his/her into the stroller or
changing his/her diaper. She /he can probably also now straighten his/her back and twist his/her trunk when he/she sits.
By 30 weeks old, your baby may be pulling himself (herself) up to a standing position and staying there for a few moments. This week your baby will also be absorbed by toys that have specific functions, such as phones.