system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did the pointed arches of Gothic architecture more efficiently support the weight of buildings, therefore allowing for taller buildings?
gpt
The real genius behind Gothic architecture wasn't so much taller buildings, which you got with earlier styles of architecture at the expense of creating dark, windowless spaces. Rather, their genius was being in able to remove so much of the walls and just leave the arches.

The innovation with the Gothic style was the so-called flying buttress, in which architects figured out how to build just enough structure to hold the place up without having to fill the whole thing in with stone. So, suddenly, these tall buildings had support structures that allowed for incredible stained glass windows to fill in most of the space. Romanesque buildings let hardly any light in. Gothic cathedrals were mostly windows -- which was a new technology at that time.

The trick was in using arches to support arches rather than using arches to support walls. Roman and Romanesque arches were round because that was the most efficient structure for holding up the weight of solid stone above them. Gothic arches are pointed because they're supported by other arches, and instead of supporting stuff above them they're really just dangling stuff below.

The most stable structure you can build with three points is a triangle, and the Gothic arch is just a modified triangle. The overall shape may not be the same, but a base at the bottom and a point at the top is, mathematically, a triangle. Put a bunch of Gothic arches together, you've really just got a bunch of overlapping triangles. Overlap enough triangles, you don't need that much crap filling in the space within them in order to hold them up.

Build with rectangles, though? If you don't make those walls solid, they're going to fall down.