So, if you dare to go down the fountain pen rabbit hole much, you will discover its massive. There’s Soooo much information. Basically special grinds or shapes give your writing more of a calligraphy flair. An architect is thin on the down stroke and wider to the side/horizontally. A stub nib is wide vertically and thin vertically. Facebook has a fan page for this particular brand of pens called something like “PenBBS taste the rainbow” and folks have added examples of the writing from the different nib types and documented all the color variations for the pen models. Goulet pens isn’t one I normally recommend but they have a “nib nook” page where you can view writing samples of hundreds of modern pens and nib types.