A computer designed by hobbyists to look like a brain on display at a Berlin fair in 2012. What happens when we go from crude models to complete working simulations of this all-important organ? Britta Pedersen/DPA/AFP/Getty Images hide caption

itoggle caption Britta Pedersen/DPA/AFP/Getty Images

Swarms of locusts in Madagascar, or clouds of elementary particles, without sound, odor, flavor or color? Reality is harder to pin down than you first might think. Bilal Tarabey/AFP/Getty Images hide caption

itoggle caption Bilal Tarabey/AFP/Getty Images