Now, we would like to talk about triangles and how they are used in architecture. Due to the rigidity of triangles, and how they are very difficult to deform, unlike squares, they are used quite commonly in architecture. Plus triangles can be used to create interesting aesthetic features, like the picture above.
With modern architecture on the rise, it has brought a less commonly used shape to the world of architecture, the circle. In the past the circle wasn't commonly used because it was just too difficult to accomplish. Now that we have the proper tools to use circles in architecture, we have found them to be quite pleasing to the eye. They serve no other purpose other than to look good, and most people find the soft roundness of circles to be quite pleasing.
What are keystones? What is their purpose? When were they used? I will tell you all about this. A key stone is the big rock at the top of an arch, Its purpose is to distribute weigh across the arch to hold up lots of weight.
This type of arch was used way back when and mostly found in church cathedrals. You can also find this type of arch in bridges to let water through. Their only purpose is to hold tons of weight and look good while doing it.