A [b]happy number[/b] is a number which eventually reaches 1 when the number is replaced by the sum of the square of each digit.[br][br]For example:[br]208 -> 2² + 0² + 8² = 68[br]68 -> 6² + 8² = 100[br]100 -> 1² + 0² + 0² = 1[br][br]Thus 208 is a [b]happy number[/b]!

The x and y co-ordinates together represent one number. [br]E.g. (20,8) = 208[br][br]This is an adaptaion from the geogebra applet[br]https://www.geogebra.org/m/SAd8TBPQ[br](by [url=https://www.geogebra.org/u/t.spillane]t.spillane[/url])