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I said I’d read that the difference in the Earth's radius between the Poles and the Equator was of the same order of sticking a postage stamp onto a football

http://fer3.com/arc/m2.aspx/Scale-Intercept-DavidPike-feb-2020-g46973 . 

As no-one was tempted to correct me, I thought it worth checking myself.  Neglecting mountains and the ocean floor, the radius of the Earth is deemed to be 6357km at the Poles and 6378km at the Equator*.  That’s a difference of 21km in 6357, or 1 in 302.  If a generously thick postage stamp is 0.005”, a pile of 302 of them would be 1.5” high, so the difference in Earth radii would be better described as sticking a postage stamp on either side of a cricket or baseball.  However, spin bowlers, please don’t try this in a test match; the umpires will never let you get away with it. DaveP

* Wikipedia