2 ball questions

(1) Find the maximum number of balls of equal size such that you can place each one to touch the rest.

(2) Same as 1. But you can choose any size of a ball. (They do not have to be the same) The second one could be hard. I remember a guy solved the problem for disks (no overlap) about 100 year ago. (and the answer is 4?)

In 1611, Kepler proposed that close packing (either cubic or hexagonal close packing. Do you think (2) is some how having a flavor of that?

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• 回复：2 ball questions -nwodedispu- ♀ (51 bytes) () 01/18/2004 postreply 08:01:00

• 回复：2 ball questions -yma16- ♀ (51 bytes) () 01/18/2004 postreply 21:15:00