There are billions of humans on planet earth, and every one of us is different. We have different races, nationalities, religions, cuisines, climates, fashions, traditions and ways of doing things.
And not just in the here-and-now, these all reach back millennia, and have developed over hundreds of years. This is a treasure trove of knowledge for learning how to think sideways.
Some cultures and civilisations are somewhat similar, owing to geographical proximity, while others are completely and utterly unalike. How, why and where did these differences arise. What thought-processes lead to different routes been taken by each of these people. In many cases, the local environment would have impacted, or some other immutable factor, but in many cases it was decisions and planning done by individuals or groups that lead to these differences.
By looking at these results and differences, we can attempt to extrapolate the steps in approach, and see where the divergences happened, and how a sudden spark set each of these cultures on completely different paths, even though they may have been seeking the same outcome at the beginning.
Much like all of the suggestions in this series, the goal here is to try identify the reason the idea or barrier that allowed the final result to come to fruition. And when you do find this, examine it to see how your thought patterns differ from it.