Arial was originally it's own font (Monotype Grotesque), but got squished to match Helvetica's metrics which is a good example of how fonts can be different and similar to each other.
As you can see, all the areas in which Monotype Arial is different from Linotype Helvetica are borrowed from Monotype Grot. The reason to make such a monster is purely financial.
As you can see, all the areas in which Monotype Arial is different from Linotype Helvetica are borrowed from Monotype Grot. The reason to make such a monster is purely financial.