Without reading a single one of the previous replies, I just know that every one of them says "a decimal point"  . But you can take what I am about to say as "a maliced point", or merely as "a claimed point", but I think of it as "a medical point": It causes unhealthy frustration on the flooblers when you slam the puzzle shut with such "a mean topic lid". (But what do I know ? I'm just an..... idiot placeman !!!!)