Ludwig Schläfli discovered the regular polytopes in $\mathbb{R}^4$, including the 24-cell, 120-cell, and 600-cell, among many results of n-dimensional geometry, between 1850 and 1852. He wrote up his results in a big manuscript, Theorie der vielfachen Kontinuität, which was rejected by the Vienna Akademie, and also in Berlin. It was finally published after his death, in 1901. In the meantime, the regular polytopes had been rediscovered by Stringham in 1880. See Coxeter's "Regular Polytopes" and the Wikipedia article on Schläfli.
Ludwig Schläfli discovered the regular polytopes in $\mathbb{R}^4$, including the 24-cell, 120-cell, and 600-cell, among many results of n-dimensional geometry, between 1850 and 1852. He wrote up his results in a big manuscript, Theorie der vielfachen Kontinuität, which was rejected by the Vienna Akademie, and also in Berlin. It was finally published after his death, in 1901. In the meantime, the regular polytopes had been rediscovered by Stringham in 1880. See Coxeter's "Regular Polytopes" and the Wikipedia article on Schläfli.
Ludwig Schläfli discovered the regular polytopes in $\mathbb{R}^4$, including the 24-cell, 120-cell, and 600-cell, among many results of n-dimensional geometry, between 1850 and 1852. He wrote up his results in a big manuscript, Theorie der vielfachen Kontinuität, which was rejected by the Vienna Akademie, and also in Berlin. It was finally published after his death, in 1901. In the meantime, the regular polytopes had been rediscovered by Stringham in 1880. See Coxeter's "Regular Polytopes" and the Wikipedia article on Schläfli.