MODULAR The components come in basic pieces and standard colors. Putting them together is the ultimate in individual dressing. BY MARY M. KASE Responding to requests from customers, Units has come out with a new piece, a "pyramid"- style jacket. It is worn over a one-piece dress and a cowl. The outfit costs around $90. 74 IN STYLE 0 you sometimes think this spring's colors were se- lected to clash with last year's? What do you do when fashion says skirts are short and tight and you're short and — well — not as firm as you once were? Or, perhaps, are just tired of trying to blend this spring's fashions into what you already have in your closet? Sounds like you're a candidate for modular dressing, a concept in which comfort, affordability and function are key, and seasonal changes, regional preferences and trends are ignored. The concept was originated in