Playing with your 4 month old

What activities are you doing with your 4 month old?

I had 3 months down pat! Playing with her with her rattles, singing, dancing, talking, tummy time, walking around, looking at things outside! Endless activities! But now that she’s 4 months...those things don’t work as well anymore. It seems like she’s really only entertained with her piano gym and a little bit of singing and dancing.