You have an ink stamp that is so amazingly precise that, when inked and pressed down on the plane, it makes every circle whose radius is an irrational number (centered at the center of the stamp) black.

Is it possible to use the stamp three times and make every point in the plane black?

If it is possible, where would you center the three stamps?

There are many more irrationals than rationals. So this may be possible.

How, I'll have to think about.
Edited on December 1, 2003, 2:00 pm

Posted by Charlie on 2003-12-01 13:58:24