One of the best things about the vest is that, even with a 3 month old at home, it only took me about a week to make.
This is the basic version of the vest. I followed the pattern and did not add any emballishments. However, following Garnituren's suggestions it is very easy to add a pocket, trimmings or buttons.
Also changing the pattern in the back shouldn't be difficult. I was tempted to make an anchor, fitting the color scheme, but it will have to wait till next time.
The website says that this is a size for a 9 months old but my 3 month old son fits pretty well into it. It is maybe a little loose and will serve him for a while but it is not too big to use.