[5]

在一張長方形的桌麵上放了n個一樣大小滴硬幣。這些硬幣中可能有一些不完全在桌麵內，也可能有一些彼此重疊；當再多放一個硬幣而它的在桌麵內時，新放的硬幣便必定與原先某些硬幣重疊。

1- from known - all points on table must be less than 2R away from at least one given 圓心;

2- Let's make all coins twice larger (R->2R).

3- based on 1- this table should be completly covered by n enlarged coins.

4- Duplicate the layout in step 3 to four tables and 4n enlarged coins

5- I can prove 4 tables are completly covered with 4n enlarged coins.

6- Now I reduce everything by 100% - so I have ONE regular table coverd with 4n REGULAR coins.