Within the top left-hand quarter of a square(its side an integer below 40 cm) I marked two points, each of which was distant an integral number of cm, not only from each side of the square but also from both the top left-hand corner and the bottom right-hand corner of the square.
What size was a side of this square?
Based on Enigma problem (New Scientist 2010)
To eliminate redundant solutions please insert the word odd
to make the remark in the brackets "its side an ODD integer below 40 cm."