Small flies: For this Kandinsky-like image, researchers stained cross sections of 20 fruit fly embryos with antibodies to reveal three distinct tissue types: muscle, nerve and skin. Recently included in Princeton University’s annual Art of Science ex­hibition, the image shows the progress made in this type of microscopy. The scientists, who come from Princeton and the Georgia Institute of Technology, developed a new micro­fluidic device that traps and vertically positions tiny objects faster than before.