In the baby books that I read semi-constantly it says that at this age (3.5 months) my baby should be able to sit up supported on pillows for a period of time. What these books do not know is that Alex has been propping Zach up for a while now, really just to make us laugh. He looks like such a little man "sitting".
This weekend he got to do more sitting on the couch with his friend Chris and his dad. He even used his arm rest.