Postcard No. 5 should really have had the subject of Mambo, instead it is another abstract, mixed-media. This time featuring a ferris wheel. Many of these wheels have popped up over the world in recent years.
If you read the wikipedia page, you find that they say the original Ferris wheel was designed by George Washington Gale Ferris Jr for the Exposition in Chicago in 1893. This is clearly where the name Ferris comes from. However, there have been 'Great Wheels' for a lot longer.
As far back as 1615, Pietro Della Valle, sent letters from Constantinople describing riding on the Great Wheel at a Ramadan Festival. "I was delighted to find myself swept upwards and downwards at such speed. But the wheel turned round so rapidly that a Greek who was sitting near me couldn't bear it any long and shouted 'soni! soni!' (enough" enough!)." These Great Wheels were chairs suspended on wooden rings turned by strong men.