Need help finding a pattern

[Ingrid]

At the bottom, yeah...I'm not sure I completely understand. Square...?

You linked to a cocoon. . . which did you mean?

[suzeeq]

I think he's too big for one of those cocoons. Sweaters are easier than you think, especially top down seamless ones. Pick a size that he's going to be able to wear in the fall - he's going to grow faster than you think. It'll probably be too warm for a sweater in just a month or two, so I'd go with a 12 mo size.