The 3D Master artist and former NASA worker Kurt Wenner uses his mathematical skill to create illusions on cobbles and pavements across the world.

　　曾为美国宇航局工作的3D粉笔画大师库特·维纳，喜欢在人行道或石子路上展开自己丰富的想象，为世界各国带来让人叹为观止的超越现实之作。