In the whimsical world of car frames, it’s a tale of evolution from the sturdy perimeter frame to the sleek Unibody. Picture cars shedding weight like they’re on a cosmic diet, swapping hefty C-rails for the svelte Hat style. The 1930s Citroens were ahead of their time, while the 60s saw Ford and Chevy in a game of frame Tetris. Think of frames as vehicular yoga, mastering the art of flex without breaking a sweat. And remember, the X-frame was the cool kid until the 60s, offering a snazzy low profile but zero side protection!