There was a curious, but telling, contrast of geopolitical images this week. While U.S. President Donald Trump was pursuing uber-opulence in Riyadh, traipsing along purple carpets, inspecting plans for glittering Saudi cities of the future and looking to collect the keys to the most decked-out private jet in history, his geopolitical opposite, China’s Xi Jinping, was speaking to the leaders of Latin America and the Caribbean in a very drab conference centre in Beijing.