( a, b, c, e) Adapted from Ref. [2
]; (d) Adapted from Ref. [1
(a) Temperature distribution in a uniform medium connecting a hot (bottom) and a cold region (top). (b) The distribution is distorted in the presence of an obstacle (an air bubble in this example). (c) Adding a thermal cloak restores the transient diffusion and isothermal lines all around the obstacle. (d) Cross section of sample used by Han et al. . (e) Cross section of molded cloak used by Xu et al. .