Cornwall-on-Hudson is built on a hill, and the morning after an ice storm every street off Hudson Street is a lesson in gravity. RANDAZZO'S INC handles that grade — plowing drives and lots, shoveling steps and walks, laying salt and sand where a slope won't forgive a miss — and keeps those same properties mowed, trimmed and edged from thaw to leaf-fall. Steep work is careful work; a plow on a pitched driveway is mostly a question of where the snow ends up. The payoff comes at breakfast time, when boots find grit instead of glass. By June the hill is green again and the mowers go up it.