Watch where you’re stepping at City Center Bishop Ranch on several Sundays throughout the Spring and Summer. At your feet, you’ll see bright and colorful chalk art done by several artists who’ve spent hours on hands and knees drawing in vivid pastels. If you miss seeing the artists in action, don’t worry. You’ll have some extra weeks to see how their efforts — using French pastels and working in a tradition that dates from Renaissance Italy — have transformed Alexander Square into a bright and colorful canvas.