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  "body": "\n## Summary\n\nThe kissing number $\\tau(n)$ is the largest number of non-overlapping unit balls in $\\R^n$ that can all touch one central unit ball.\nIt is known exactly only in dimensions $1$, $2$, $3$, $4$, $8$ and $24$, where it equals $2$, $6$, $12$, $24$, $240$ and $196560$.\nThe problem is a close relative of [[sphere packing|HF32CBN5MA]] and of the theory of [[spherical codes|SDCX4WDP4F]].\n\n## Explanations\n\n### L1 human\n\nPut one coin on a table and ask how many equal coins can touch it without overlapping each other.\nThe answer is six, and they fit perfectly around it.\nFor balls in space the answer is twelve, but here there is some room to spare, which made the question hard.\nIn higher dimensions the numbers grow very quickly and are mostly unknown.\n",
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