Ideas?

This week I'm appealing to you for your ideas.  I've been spending a lot of time on the couch below and it's been so interesting to how certain things can hold Carson's attention for a long time. 
These are the two things in our house that he constantly stares at:

I can set him on the couch and come back 10 minutes later (on a good day when he's not crying...) and he's still staring at the pillows or the painting.  And when I hold him he cranes his neck to see one of these items.
I've heard about how contrasting colors like black and white are easiest for newborns to see so it makes sense.  And I guess since the painting has light and dark colors that it's interesting to him.  Kinda cool how true it is.

Anyway, I've been wanting to make something else that would be interesting and stimulating for him.  I've considered making a mobile - maybe also black and white or constrasting colors. 

What things have been interesting to your infants?  Ideas, anyone...?