The study of shapes and spaces in four dimensions, where the fourth dimension is typically considered time or an additional spatial dimension beyond our familiar three. In 4D geometry, objects have four mutually perpendicular axes, allowing for forms that would seem impossible in 3D—like the tesseract (a 4D cube), which projects into our world as a cube within a cube with connecting lines that don't actually touch. 4D geometry explains why your keys seem to disappear into thin air (they've merely shifted into the fourth dimension) and why your phone is always in the last place you look (you're only checking three dimensions). It's the geometry of time travelers, interdimensional beings, and anyone who's ever said "it's in another dimension" as an excuse.
Example: "He tried to explain 4D geometry to his friend by describing a tesseract—a cube within a cube with all corners connected. His friend asked if that was like Inception. He said no, it was like a cube that also exists in time. His friend asked if that was like a movie. He gave up and said 'it's complicated,' which is 4D geometry's favorite phrase."
by AbzuInExile February 16, 2026
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